Initial commit

.gitattributes

@@ -0,0 +1,12 @@
+*.c linguist-detectable=true
+*.cmake linguist-detectable=false
+*.py linguist-detectable=false
+*.txt linguist-detectable=false
+*.json linguist-detectable=false
+*.ps1 linguist-detectable=false
+
+# Line endings: store LF in the repository; check out LF everywhere except the
+# Windows PowerShell scripts, which stay CRLF. Prevents CRLF<->LF churn.
+* text=auto eol=lf
+*.ps1 text eol=crlf
+

.gitignore

@@ -0,0 +1,83 @@
+# Prerequisites
+*.d
+
+# Object files
+*.o
+*.ko
+*.obj
+*.elf
+
+# Linker output
+*.ilk
+*.map
+*.exp
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Libraries
+*.lib
+*.a
+*.la
+*.lo
+
+# Shared objects (inc. Windows DLLs)
+*.dll
+*.so
+*.so.*
+*.dylib
+
+# Executables
+*.exe
+*.out
+*.app
+*.i*86
+*.x86_64
+*.hex
+
+# Debug files
+*.dSYM/
+*.su
+*.idb
+*.pdb
+*.rep
+*.gpr
+
+# Kernel Module Compile Results
+*.mod*
+*.cmd
+.tmp_versions/
+modules.order
+Module.symvers
+Mkfile.old
+dkms.conf
+
+# Build output
+build/
+target/
+
+# Node.js and PDF generation script
+node_modules/
+package-lock.json
+package.json
+svg-to-pdf.ps1
+
+# Operating System Files
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+
+# Logs written by the Binary Ninja console helpers (build / flash / OpenOCD)
+openocd.log
+flash.log
+build.log
+build-flash.log
+
+# Nested repositories
+eCTF/
+

0x0001_hello-world/.gitignore

@@ -0,0 +1,2 @@
+build
+!.vscode/*

0x0001_hello-world/.vscode/c_cpp_properties.json

@@ -0,0 +1,22 @@
+{
+    "configurations": [
+        {
+            "name": "Pico",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "${userHome}/.pico-sdk/sdk/2.2.0/**"
+            ],
+            "forcedInclude": [
+                "${userHome}/.pico-sdk/sdk/2.2.0/src/common/pico_base_headers/include/pico.h",
+                "${workspaceFolder}/build/generated/pico_base/pico/config_autogen.h"
+            ],
+            "defines": [],
+            "compilerPath": "${userHome}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json",
+            "cStandard": "c17",
+            "cppStandard": "c++14",
+            "intelliSenseMode": "linux-gcc-arm"
+        }
+    ],
+    "version": 4
+}

0x0001_hello-world/.vscode/cmake-kits.json

@@ -0,0 +1,15 @@
+[
+    {
+        "name": "Pico",
+        "compilers": {
+            "C": "${command:raspberry-pi-pico.getCompilerPath}",
+            "CXX": "${command:raspberry-pi-pico.getCxxCompilerPath}"
+        },
+        "environmentVariables": {
+            "PATH": "${command:raspberry-pi-pico.getEnvPath};${env:PATH}"
+        },
+        "cmakeSettings": {
+            "Python3_EXECUTABLE": "${command:raspberry-pi-pico.getPythonPath}"
+        }
+    }
+]

0x0001_hello-world/.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+    "recommendations": [
+        "marus25.cortex-debug",
+        "ms-vscode.cpptools",
+        "ms-vscode.cpptools-extension-pack",
+        "ms-vscode.vscode-serial-monitor",
+        "raspberry-pi.raspberry-pi-pico"
+    ]
+}

0x0001_hello-world/.vscode/launch.json

@@ -0,0 +1,50 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Pico Debug (Cortex-Debug)",
+            "cwd": "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg"
+            ],
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ]
+        },
+        {
+            "name": "Pico Debug (Cortex-Debug with external OpenOCD)",
+            "cwd": "${workspaceRoot}",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "external",
+            "gdbTarget": "localhost:3333",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ]
+        },
+    ]
+}

0x0001_hello-world/.vscode/settings.json

@@ -0,0 +1,43 @@
+{
+    "cmake.showSystemKits": false,
+    "cmake.options.statusBarVisibility": "hidden",
+    "cmake.options.advanced": {
+        "build": {
+            "statusBarVisibility": "hidden"
+        },
+        "launch": {
+            "statusBarVisibility": "hidden"
+        },
+        "debug": {
+            "statusBarVisibility": "hidden"
+        }
+    },
+    "cmake.configureOnEdit": false,
+    "cmake.automaticReconfigure": false,
+    "cmake.configureOnOpen": false,
+    "cmake.generator": "Ninja",
+    "cmake.cmakePath": "${userHome}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "C_Cpp.debugShortcut": false,
+    "terminal.integrated.env.windows": {
+        "PICO_SDK_PATH": "${env:USERPROFILE}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1",
+        "Path": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin;${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool;${env:USERPROFILE}/.pico-sdk/cmake/v3.31.5/bin;${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1;${env:PATH}"
+    },
+    "terminal.integrated.env.osx": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "terminal.integrated.env.linux": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "raspberry-pi-pico.cmakeAutoConfigure": true,
+    "raspberry-pi-pico.useCmakeTools": false,
+    "raspberry-pi-pico.cmakePath": "${HOME}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "raspberry-pi-pico.ninjaPath": "${HOME}/.pico-sdk/ninja/v1.12.1/ninja",
+    "files.associations": {
+        "stdlib.h": "c"
+    }
+}

0x0001_hello-world/.vscode/tasks.json

@@ -0,0 +1,102 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "process",
+            "isBuildCommand": true,
+            "command": "${userHome}/.pico-sdk/ninja/v1.12.1/ninja",
+            "args": ["-C", "${workspaceFolder}/build"],
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc",
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1/ninja.exe"
+            }
+        },
+        {
+            "label": "Run Project",
+            "type": "process",
+            "command": "${env:HOME}/.pico-sdk/picotool/2.2.0/picotool/picotool",
+            "args": [
+                "load",
+                "${command:raspberry-pi-pico.launchTargetPath}",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool/picotool.exe"
+            }
+        },
+        {
+            "label": "Flash",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg",
+                "-c",
+                "adapter speed 5000; program \"${command:raspberry-pi-pico.launchTargetPath}\" verify reset exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Rescue Reset",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getChip}-rescue.cfg",
+                "-c",
+                "adapter speed 5000; reset halt; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Risc-V Reset (RP2350)",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-c",
+                "set USE_CORE { rv0 rv1 cm0 cm1 }",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; init;",
+                "-c",
+                "write_memory 0x40120158 8 { 0x3 }; echo [format \"Info : ARCHSEL 0x%02x\" [read_memory 0x40120158 8 1]];",
+                "-c",
+                "reset halt; targets rp2350.rv0; echo [format \"Info : ARCHSEL_STATUS 0x%02x\" [read_memory 0x4012015C 8 1]]; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        }
+    ]
+}

0x0001_hello-world/0x0001_hello-world.c

@@ -0,0 +1,46 @@
+/**
+ * @file 0x0001_hello-world.c
+ * @brief Hello World: print a greeting over UART in an infinite loop
+ * @author Kevin Thomas
+ * @date 2025
+ *
+ * MIT License
+ *
+ * Copyright (c) 2025 Kevin Thomas
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Demonstrates the minimal "hello, world" program on the Raspberry Pi Pico 2.
+ * Initializes stdio over UART and prints a greeting in an infinite loop.
+ *
+ * Wiring:
+ *   No external wiring required (USB serial).
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+int main(void) {
+    stdio_init_all();
+    while (true) {
+        printf("hello, world\r\n");
+    }
+}

0x0001_hello-world/CMakeLists.txt

@@ -0,0 +1,57 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.2.0)
+set(toolchainVersion 14_2_Rel1)
+set(picotoolVersion 2.2.0)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico2 CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(0x0001_hello-world C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(0x0001_hello-world 0x0001_hello-world.c )
+
+pico_set_program_name(0x0001_hello-world "0x0001_hello-world")
+pico_set_program_version(0x0001_hello-world "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(0x0001_hello-world 1)
+pico_enable_stdio_usb(0x0001_hello-world 0)
+
+# Add the standard library to the build
+target_link_libraries(0x0001_hello-world
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(0x0001_hello-world PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+pico_add_extra_outputs(0x0001_hello-world)
+

0x0001_hello-world/pico_sdk_import.cmake

@@ -0,0 +1,121 @@
+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+# Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+# following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+# disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+# disclaimer in the documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
+# derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_TAG} AND (NOT PICO_SDK_FETCH_FROM_GIT_TAG))
+    set(PICO_SDK_FETCH_FROM_GIT_TAG $ENV{PICO_SDK_FETCH_FROM_GIT_TAG})
+    message("Using PICO_SDK_FETCH_FROM_GIT_TAG from environment ('${PICO_SDK_FETCH_FROM_GIT_TAG}')")
+endif ()
+
+if (PICO_SDK_FETCH_FROM_GIT AND NOT PICO_SDK_FETCH_FROM_GIT_TAG)
+  set(PICO_SDK_FETCH_FROM_GIT_TAG "master")
+  message("Using master as default value for PICO_SDK_FETCH_FROM_GIT_TAG")
+endif()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+set(PICO_SDK_FETCH_FROM_GIT_TAG "${PICO_SDK_FETCH_FROM_GIT_TAG}" CACHE FILEPATH "release tag for SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        FetchContent_Declare(
+                pico_sdk
+                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+        )
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            # GIT_SUBMODULES_RECURSE was added in 3.17
+            if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+                        GIT_SUBMODULES_RECURSE FALSE
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            else ()
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            endif ()
+
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})

0x0001a_stack/.gitignore

@@ -0,0 +1,2 @@
+build
+!.vscode/*

0x0001a_stack/.vscode/c_cpp_properties.json

@@ -0,0 +1,22 @@
+{
+    "configurations": [
+        {
+            "name": "Pico",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "${userHome}/.pico-sdk/sdk/2.3.0/**"
+            ],
+            "forcedInclude": [
+                "${workspaceFolder}/build/generated/pico_base/pico/config_autogen.h",
+                "${userHome}/.pico-sdk/sdk/2.3.0/src/common/pico_base_headers/include/pico.h"
+            ],
+            "defines": [],
+            "compilerPath": "${userHome}/.pico-sdk/toolchain/15_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json",
+            "cStandard": "c17",
+            "cppStandard": "c++14",
+            "intelliSenseMode": "linux-gcc-arm"
+        }
+    ],
+    "version": 4
+}

0x0001a_stack/.vscode/cmake-kits.json

@@ -0,0 +1,15 @@
+[
+    {
+        "name": "Pico",
+        "compilers": {
+            "C": "${command:raspberry-pi-pico.getCompilerPath}",
+            "CXX": "${command:raspberry-pi-pico.getCxxCompilerPath}"
+        },
+        "environmentVariables": {
+            "PATH": "${command:raspberry-pi-pico.getEnvPath};${env:PATH}"
+        },
+        "cmakeSettings": {
+            "Python3_EXECUTABLE": "${command:raspberry-pi-pico.getPythonPath}"
+        }
+    }
+]

0x0001a_stack/.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+    "recommendations": [
+        "marus25.cortex-debug",
+        "ms-vscode.cpptools",
+        "ms-vscode.cpptools-extension-pack",
+        "ms-vscode.vscode-serial-monitor",
+        "raspberry-pi.raspberry-pi-pico"
+    ]
+}

0x0001a_stack/.vscode/launch.json

@@ -0,0 +1,52 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Pico Debug (Cortex-Debug)",
+            "cwd": "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "debuggerArgs": ["-ex", "set debug-file-directory /debug"],
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg"
+            ],
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.3.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ]
+        },
+        {
+            "name": "Pico Debug (Cortex-Debug with external OpenOCD)",
+            "cwd": "${workspaceRoot}",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "external",
+            "gdbTarget": "localhost:3333",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "debuggerArgs": ["-ex", "set debug-file-directory /debug"],
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.3.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ]
+        }
+    ]
+}

0x0001a_stack/.vscode/settings.json

@@ -0,0 +1,46 @@
+{
+    "cmake.showSystemKits": false,
+    "cmake.options.statusBarVisibility": "hidden",
+    "cmake.options.advanced": {
+        "build": {
+            "statusBarVisibility": "hidden"
+        },
+        "launch": {
+            "statusBarVisibility": "hidden"
+        },
+        "debug": {
+            "statusBarVisibility": "hidden"
+        },
+        "variant": {
+            "statusBarVisibility": "hidden"
+        },
+        "buildTarget": {
+            "statusBarVisibility": "hidden"
+        }
+    },
+    "cmake.configureOnEdit": false,
+    "cmake.automaticReconfigure": false,
+    "cmake.configureOnOpen": false,
+    "cmake.generator": "Ninja",
+    "cmake.cmakePath": "${userHome}/.pico-sdk/cmake/v4.3.4/bin/cmake",
+    "C_Cpp.debugShortcut": false,
+    "terminal.integrated.env.windows": {
+        "PICO_SDK_PATH": "${env:USERPROFILE}/.pico-sdk/sdk/2.3.0",
+        "PICO_TOOLCHAIN_PATH": "${env:USERPROFILE}/.pico-sdk/toolchain/15_2_Rel1",
+        "Path": "${env:USERPROFILE}/.pico-sdk/toolchain/15_2_Rel1/bin;${env:USERPROFILE}/.pico-sdk/picotool/2.3.0/picotool;${env:USERPROFILE}/.pico-sdk/cmake/v4.3.4/bin;${env:USERPROFILE}/.pico-sdk/ninja/v1.13.2;${env:PATH}"
+    },
+    "terminal.integrated.env.osx": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.3.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/15_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/15_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.3.0/picotool:${env:HOME}/.pico-sdk/cmake/v4.3.4/bin:${env:HOME}/.pico-sdk/ninja/v1.13.2:${env:PATH}"
+    },
+    "terminal.integrated.env.linux": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.3.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/15_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/15_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.3.0/picotool:${env:HOME}/.pico-sdk/cmake/v4.3.4/bin:${env:HOME}/.pico-sdk/ninja/v1.13.2:${env:PATH}"
+    },
+    "raspberry-pi-pico.cmakeAutoConfigure": true,
+    "raspberry-pi-pico.useCmakeTools": false,
+    "raspberry-pi-pico.cmakePath": "${HOME}/.pico-sdk/cmake/v4.3.4/bin/cmake",
+    "raspberry-pi-pico.ninjaPath": "${HOME}/.pico-sdk/ninja/v1.13.2/ninja"
+}

0x0001a_stack/.vscode/tasks.json

@@ -0,0 +1,102 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "process",
+            "isBuildCommand": true,
+            "command": "${userHome}/.pico-sdk/ninja/v1.13.2/ninja",
+            "args": ["-C", "${workspaceFolder}/build"],
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc",
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/ninja/v1.13.2/ninja.exe"
+            }
+        },
+        {
+            "label": "Run Project",
+            "type": "process",
+            "command": "${env:HOME}/.pico-sdk/picotool/2.3.0/picotool/picotool",
+            "args": [
+                "load",
+                "${command:raspberry-pi-pico.launchTargetPath}",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.3.0/picotool/picotool.exe"
+            }
+        },
+        {
+            "label": "Flash",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg",
+                "-c",
+                "adapter speed 5000; program \"${command:raspberry-pi-pico.launchTargetPath}\" verify reset exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe"
+            }
+        },
+        {
+            "label": "Rescue Reset",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getChip}-rescue.cfg",
+                "-c",
+                "adapter speed 5000; reset halt; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe"
+            }
+        },
+        {
+            "label": "RISC-V Reset (RP2350)",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-c",
+                "set USE_CORE { rv0 rv1 cm0 cm1 }",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; init;",
+                "-c",
+                "write_memory 0x40120158 8 { 0x3 }; echo [format \"Info : ARCHSEL 0x%02x\" [read_memory 0x40120158 8 1]];",
+                "-c",
+                "reset halt; targets rp2350.rv0; echo [format \"Info : ARCHSEL_STATUS 0x%02x\" [read_memory 0x4012015C 8 1]]; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe"
+            }
+        }
+    ]
+}

0x0001a_stack/0x0001a_stack.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+
+int main()
+{
+    stdio_init_all();
+
+    while (true) {
+        __asm volatile(
+            // Save a low register and the link register.
+            "push {r4, lr}\n"
+            // Intentionally unordered: the encoded list is still r2, r3, r6.
+            "push {r3, r2, r6}\n"
+            // Thumb PUSH cannot encode high registers r8-r12.
+            "stmdb sp!, {r9, r10}\n"
+            // Restore each group in reverse order to return SP to its start.
+            "ldmia sp!, {r9, r10}\n"
+            "pop {r2, r3, r6}\n"
+            "pop {r4, lr}\n"
+            ::: "memory");
+    }
+}

0x0001a_stack/CMakeLists.txt

@@ -0,0 +1,57 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.3.0)
+set(toolchainVersion 15_2_Rel1)
+set(picotoolVersion 2.3.0)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico2 CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(0x0001a_stack C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(0x0001a_stack 0x0001a_stack.c )
+
+pico_set_program_name(0x0001a_stack "0x0001a_stack")
+pico_set_program_version(0x0001a_stack "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(0x0001a_stack 1)
+pico_enable_stdio_usb(0x0001a_stack 0)
+
+# Add the standard library to the build
+target_link_libraries(0x0001a_stack
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(0x0001a_stack PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+pico_add_extra_outputs(0x0001a_stack)
+

0x0001a_stack/pico_sdk_import.cmake

@@ -0,0 +1,121 @@
+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+# Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+# following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+# disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+# disclaimer in the documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
+# derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_TAG} AND (NOT PICO_SDK_FETCH_FROM_GIT_TAG))
+    set(PICO_SDK_FETCH_FROM_GIT_TAG $ENV{PICO_SDK_FETCH_FROM_GIT_TAG})
+    message("Using PICO_SDK_FETCH_FROM_GIT_TAG from environment ('${PICO_SDK_FETCH_FROM_GIT_TAG}')")
+endif ()
+
+if (PICO_SDK_FETCH_FROM_GIT AND NOT PICO_SDK_FETCH_FROM_GIT_TAG)
+  set(PICO_SDK_FETCH_FROM_GIT_TAG "master")
+  message("Using master as default value for PICO_SDK_FETCH_FROM_GIT_TAG")
+endif()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+set(PICO_SDK_FETCH_FROM_GIT_TAG "${PICO_SDK_FETCH_FROM_GIT_TAG}" CACHE FILEPATH "release tag for SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        FetchContent_Declare(
+                pico_sdk
+                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+        )
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            # GIT_SUBMODULES_RECURSE was added in 3.17
+            if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+                        GIT_SUBMODULES_RECURSE FALSE
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            else ()
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            endif ()
+
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})

0x0001b_ctf/.gitignore

@@ -0,0 +1,4 @@
+build
+!.vscode/*
+!build-ctf/0x0001b_ctf.bin
+!CTF-01.bin

0x0001b_ctf/.vscode/c_cpp_properties.json

@@ -0,0 +1,22 @@
+{
+    "configurations": [
+        {
+            "name": "Pico",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "${userHome}/.pico-sdk/sdk/2.3.1/**"
+            ],
+            "forcedInclude": [
+                "${workspaceFolder}/build/generated/pico_base/pico/config_autogen.h",
+                "${userHome}/.pico-sdk/sdk/2.3.1/src/common/pico_base_headers/include/pico.h"
+            ],
+            "defines": [],
+            "compilerPath": "${userHome}/.pico-sdk/toolchain/15_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json",
+            "cStandard": "c17",
+            "cppStandard": "c++14",
+            "intelliSenseMode": "linux-gcc-arm"
+        }
+    ],
+    "version": 4
+}

0x0001b_ctf/.vscode/cmake-kits.json

@@ -0,0 +1,15 @@
+[
+    {
+        "name": "Pico",
+        "compilers": {
+            "C": "${command:raspberry-pi-pico.getCompilerPath}",
+            "CXX": "${command:raspberry-pi-pico.getCxxCompilerPath}"
+        },
+        "environmentVariables": {
+            "PATH": "${command:raspberry-pi-pico.getEnvPath};${env:PATH}"
+        },
+        "cmakeSettings": {
+            "Python3_EXECUTABLE": "${command:raspberry-pi-pico.getPythonPath}"
+        }
+    }
+]

0x0001b_ctf/.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+    "recommendations": [
+        "marus25.cortex-debug",
+        "ms-vscode.cpptools",
+        "ms-vscode.cpptools-extension-pack",
+        "ms-vscode.vscode-serial-monitor",
+        "raspberry-pi.raspberry-pi-pico"
+    ]
+}

0x0001b_ctf/.vscode/launch.json

@@ -0,0 +1,52 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Pico Debug (Cortex-Debug)",
+            "cwd": "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "debuggerArgs": ["-ex", "set debug-file-directory /debug"],
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg"
+            ],
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.3.1/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ]
+        },
+        {
+            "name": "Pico Debug (Cortex-Debug with external OpenOCD)",
+            "cwd": "${workspaceRoot}",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "external",
+            "gdbTarget": "localhost:3333",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "debuggerArgs": ["-ex", "set debug-file-directory /debug"],
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.3.1/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ]
+        }
+    ]
+}

0x0001b_ctf/.vscode/settings.json

@@ -0,0 +1,46 @@
+{
+    "cmake.showSystemKits": false,
+    "cmake.options.statusBarVisibility": "hidden",
+    "cmake.options.advanced": {
+        "build": {
+            "statusBarVisibility": "hidden"
+        },
+        "launch": {
+            "statusBarVisibility": "hidden"
+        },
+        "debug": {
+            "statusBarVisibility": "hidden"
+        },
+        "variant": {
+            "statusBarVisibility": "hidden"
+        },
+        "buildTarget": {
+            "statusBarVisibility": "hidden"
+        }
+    },
+    "cmake.configureOnEdit": false,
+    "cmake.automaticReconfigure": false,
+    "cmake.configureOnOpen": false,
+    "cmake.generator": "Ninja",
+    "cmake.cmakePath": "${userHome}/.pico-sdk/cmake/v4.3.4/bin/cmake",
+    "C_Cpp.debugShortcut": false,
+    "terminal.integrated.env.windows": {
+        "PICO_SDK_PATH": "${env:USERPROFILE}/.pico-sdk/sdk/2.3.1",
+        "PICO_TOOLCHAIN_PATH": "${env:USERPROFILE}/.pico-sdk/toolchain/15_2_Rel1",
+        "Path": "${env:USERPROFILE}/.pico-sdk/toolchain/15_2_Rel1/bin;${env:USERPROFILE}/.pico-sdk/picotool/2.3.1/picotool;${env:USERPROFILE}/.pico-sdk/cmake/v4.3.4/bin;${env:USERPROFILE}/.pico-sdk/ninja/v1.13.2;${env:PATH}"
+    },
+    "terminal.integrated.env.osx": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.3.1",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/15_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/15_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.3.1/picotool:${env:HOME}/.pico-sdk/cmake/v4.3.4/bin:${env:HOME}/.pico-sdk/ninja/v1.13.2:${env:PATH}"
+    },
+    "terminal.integrated.env.linux": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.3.1",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/15_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/15_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.3.1/picotool:${env:HOME}/.pico-sdk/cmake/v4.3.4/bin:${env:HOME}/.pico-sdk/ninja/v1.13.2:${env:PATH}"
+    },
+    "raspberry-pi-pico.cmakeAutoConfigure": true,
+    "raspberry-pi-pico.useCmakeTools": false,
+    "raspberry-pi-pico.cmakePath": "${HOME}/.pico-sdk/cmake/v4.3.4/bin/cmake",
+    "raspberry-pi-pico.ninjaPath": "${HOME}/.pico-sdk/ninja/v1.13.2/ninja"
+}

0x0001b_ctf/.vscode/tasks.json

@@ -0,0 +1,102 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "process",
+            "isBuildCommand": true,
+            "command": "${userHome}/.pico-sdk/ninja/v1.13.2/ninja",
+            "args": ["-C", "${workspaceFolder}/build"],
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc",
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/ninja/v1.13.2/ninja.exe"
+            }
+        },
+        {
+            "label": "Run Project",
+            "type": "process",
+            "command": "${env:HOME}/.pico-sdk/picotool/2.3.1/picotool/picotool",
+            "args": [
+                "load",
+                "${command:raspberry-pi-pico.launchTargetPath}",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.3.1/picotool/picotool.exe"
+            }
+        },
+        {
+            "label": "Flash",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg",
+                "-c",
+                "adapter speed 5000; program \"${command:raspberry-pi-pico.launchTargetPath}\" verify reset exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe"
+            }
+        },
+        {
+            "label": "Rescue Reset",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getChip}-rescue.cfg",
+                "-c",
+                "adapter speed 5000; reset halt; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe"
+            }
+        },
+        {
+            "label": "RISC-V Reset (RP2350)",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-c",
+                "set USE_CORE { rv0 rv1 cm0 cm1 }",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; init;",
+                "-c",
+                "write_memory 0x40120158 8 { 0x3 }; echo [format \"Info : ARCHSEL 0x%02x\" [read_memory 0x40120158 8 1]];",
+                "-c",
+                "reset halt; targets rp2350.rv0; echo [format \"Info : ARCHSEL_STATUS 0x%02x\" [read_memory 0x4012015C 8 1]]; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe"
+            }
+        }
+    ]
+}

0x0001b_ctf/CMakeLists.txt

@@ -0,0 +1,91 @@
+# MIT License
+#
+# Copyright (c) 2026 Kevin Thomas
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+#
+# Author:  Kevin Thomas
+# Email:   kevin@mytechnotalent.com
+# GitHub:  https://github.com/mytechnotalent
+# File:    CMakeLists.txt
+# Desc:    Configures the RP2350 Pico SDK project for the Operation Black Start
+#          CTF relay firmware.
+# Created: 2026
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.3.1)
+set(toolchainVersion 15_2_Rel1)
+set(picotoolVersion 2.3.1)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico2 CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(0x0001b_ctf C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable with modular sources in src/
+add_executable(0x0001b_ctf
+    src/main.c
+    src/grid.c
+    src/console.c
+)
+
+pico_set_program_name(0x0001b_ctf "0x0001b_ctf")
+pico_set_program_version(0x0001b_ctf "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(0x0001b_ctf 1)
+pico_enable_stdio_usb(0x0001b_ctf 0)
+target_compile_definitions(0x0001b_ctf PRIVATE
+    PICO_DEFAULT_UART_BAUD_RATE=115200
+)
+
+# Add the standard library to the build
+target_link_libraries(0x0001b_ctf
+    pico_stdlib
+)
+
+# Add the standard include files to the build
+target_include_directories(0x0001b_ctf PRIVATE
+    ${CMAKE_CURRENT_LIST_DIR}/include
+)
+
+pico_add_extra_outputs(0x0001b_ctf)

0x0001b_ctf/CTF-01-I.md

@@ -0,0 +1,442 @@
+# Operation Black Start - Student Instructions
+
+**⚠ WORLDGRID EMERGENCY INCIDENT ⚠**
+
+```
++----------------------------------------------------------------------------------------+
+|                                                                                        |
+|   ██████╗ ██╗      █████╗  ██████╗██╗  ██╗███████╗████████╗ █████╗ ██████╗ ████████╗   |
+|   ██╔══██╗██║     ██╔══██╗██╔════╝██║ ██╔╝██╔════╝╚══██╔══╝██╔══██╗██╔══██╗╚══██╔══╝   |
+|   ██████╔╝██║     ███████║██║     █████╔╝ ███████╗   ██║   ███████║██████╔╝   ██║      |
+|   ██╔══██╗██║     ██╔══██║██║     ██╔═██╗ ╚════██║   ██║   ██╔══██║██╔══██╗   ██║      |
+|   ██████╔╝███████╗██║  ██║╚██████╗██║  ██╗███████╗   ██║   ██║  ██║██║  ██║   ██║      |
+|   ╚═════╝ ╚══════╝╚═╝  ╚═╝ ╚═════╝██║  ██║╚══════╝   ╚═╝   ╚═╝  ╚═╝██║  ██║   ██║      |
+|                                                                                        |
+|                                                                                        |
+|                       O P E R A T I O N   B L A C K   S T A R T                        |
+|                                                                                        |
+|                                  *** PRIORITY RED ***                                  |
+|                                                                                        |
++----------------------------------------------------------------------------------------+
+```
+
+---
+
+## Project Overview
+
+WorldGrid Compact's emergency firmware build for its GRID-7 relay fleet
+shipped a miscompiled safety threshold and a hardcoded false status string,
+so deployed relays report a false-safe "STABLE" status while the frozen
+frequency deviation reading of 0.87 Hz is nearly 50% beyond the 0.60 Hz
+engineering limit. The source was overwritten by the next build and cannot
+be recovered, so the only surviving evidence is the exact miscompiled
+training image. Students reverse engineer `CTF-01.bin` with Ghidra, locate
+and patch both defects directly in the binary, export a corrected image,
+flash it to a Pico 2, and prove the corrected behavior with GDB and a UART
+console.
+
+---
+
+## Scenario Briefing
+
+### Background
+
+**WorldGrid Compact** is the emergency interconnection standard shared by
+three allied national grid operators. When any member's primary SCADA
+network goes dark, a fleet of small embedded relay nodes - call sign
+**GRID-7** - is the only thing standing between an orderly recovery and an
+uncontrolled cascade. Each relay node watches the last known grid frequency
+deviation, decides whether conditions are safe, and either **holds** the
+automatic black-start dispatch or **authorizes** it.
+
+At 03:11 UTC, a coordinated cyberattack severed the primary SCADA uplink
+across the GRID-7 corridor and the WATER-3 aqueduct pumping stations that
+depend on it. With the network coordination center offline and three
+continents' worth of hospitals, rail systems, and water treatment plants
+running on backup power, WorldGrid's engineering team did the only thing
+they could: they rushed an emergency firmware build for the relay fleet and
+pushed it within **eleven minutes** of the attack being detected.
+
+### The Disaster
+
+The engineer who built that emergency image, **Dr. Elias Renner**, has not
+slept in thirty-one hours. He compiled the fix, ran a five-second bench
+test, and shipped it - because the alternative was leaving the relay fleet
+completely blind. It appears to work. The relay boots. It prints a status
+report. It reports **GRID STATUS: STABLE** and **DISPATCH PATH:
+AUTHORIZED**.
+
+There is a problem: the frozen frequency reading latched at the moment
+communications were cut shows a deviation of **0.87 Hz** - nearly *50%
+beyond* WorldGrid's hard engineering limit of **0.60 Hz**. A deviation this
+large, if trusted, means the grid is nowhere near stable enough for an
+automatic black-start dispatch. If the fleet authorizes dispatch on a false
+"STABLE" reading, cascading generator trips will follow within minutes,
+and GRID-7 and WATER-3 will go dark for the second time - this time with no
+backup plan.
+
+**Dr. Renner's rushed build has a bug. Multiple relay nodes are already
+reporting the same false-safe status. Nobody has found where in the
+compiled firmware the error lives, because the source code used for that
+emergency compile was overwritten by the next build fifteen minutes later
+and cannot be recovered.**
+
+### The Only Surviving Evidence
+
+One relay node - the training/verification unit - still holds the exact
+miscompiled image that shipped to the fleet. This binary, and this binary
+alone, is the only remaining copy of the emergency build. There is no
+source code. There is no build log. There is only the compiled image, a
+UART cable, and whatever a skilled embedded reverse engineer can prove by
+reading machine code.
+
+###  The Human Stakes
+
+| Consequence if the false "STABLE" reading is trusted | Scale |
+|---|---|
+| Hospitals on generator backup past their fuel reserve | 214 facilities |
+| Water treatment and pumping stations losing pressure | 3 aqueduct systems |
+| Rail corridors stranded mid-route | 6 national rail networks |
+| Estimated population affected by cascading failure | 40+ million people |
+
+**The options are:**
+
+1. ❌ **Trust the fleet's reported status** - dispatch fires on a false
+   reading, cascading failure follows within the hour.
+2. ❌ **Shut the entire relay fleet down** - buys time, but leaves 40
+   million people with no automated recovery path at all.
+3.  **REVERSE ENGINEER THE EMERGENCY BUILD** - find the exact
+   miscompiled bytes, patch them, verify the corrected image on real
+   hardware, and hand the fix to the field team so the *rest of the fleet*
+   can be safely repatched before the next attempt.
+
+### THE SHORTAGE
+
+For years, the world treated embedded systems as invisible infrastructure.
+The engineers who could read a vector table, decode a Thumb branch, or
+patch a miscompiled constant directly in a stripped binary were never
+numerous enough. Tonight almost all of them are already in the field
+chasing other failures. **You are the reserve team.**
+
+You were called in because you can do something Dr. Renner's exhausted
+team cannot do right now: read what the processor is actually doing, with
+no source code, no time for a rewrite, and no room for a guess.
+
+> **⏰ TIME PRESSURE:** The field team is standing by to push your verified
+> patch to the rest of the GRID-7 fleet. Every relay node still reporting
+> a false "STABLE" status is one dispatch cycle away from disaster.
+
+> **AUTHORIZED LAB ONLY:** This challenge uses a supplied Pico 2 training
+> relay and its exact miscompiled firmware image. Do not connect this
+> exercise to a public network, an operational grid, a water utility, or
+> any device you do not own or have explicit written authorization to test.
+
+---
+
+## Learning Objectives
+
+- Decode the RP2350 / ARM Cortex-M33 vector table and identify the reset
+  handler and initial stack pointer.
+- Trace the bootrom-to-reset handoff and translate Thumb reset-vector
+  addresses into real function entry points.
+- Locate a miscompiled boundary comparison and reason about the correct
+  immediate value the compiler should have encoded.
+- Patch compare instructions and a status string directly in a raw binary
+  with Ghidra.
+- Recover a hidden quarantined dispatch frame from the compiled image.
+- Export and UF2-convert a corrected image, then verify the corrected
+  behavior on real hardware with GDB and a UART console.
+
+---
+
+## What This Project Tests
+
+| Week | Concepts Tested |
+|------|-----------------|
+| 1 | RP2350 architecture, ARM Cortex-M33 registers, stack, flash/RAM, Thumb assembly, Ghidra static analysis |
+| 2 | GDB connection, breakpoints, disassembly, register and memory inspection, UART observation |
+| 3 | Bootrom handoff, vector table, reset handler, startup code, XIP, Thumb-bit addressing |
+
+---
+
+## Part 1: Understanding the System
+
+### GRID-7 Relay Hardware
+
+| Component | Connection | Purpose |
+|-----------|------------|---------|
+| Raspberry Pi Pico 2 | RP2350 | Runs the miscompiled emergency firmware |
+| UART TX | GPIO 0 | Relay telemetry output |
+| UART RX | GPIO 1 | Reserved (no command parser is implemented) |
+| SWD debug interface | Supplied probe | Authorized GDB inspection |
+
+No LED, relay output, sensor, display, or other peripheral is part of this
+CTF. Every graded finding lives in flash (`.rodata`/`.text`) or SRAM, and is
+reachable with only the Weeks 1-3 toolset: Ghidra, GDB, and a UART monitor.
+
+### UART Configuration
+
+- Baud: `115200`
+- Data: `8 bits`
+- Parity: `none`
+- Stop: `1`
+- Logic: `3.3 V`
+
+### Normal (Intended) Behavior
+
+The relay should latch the frozen deviation reading, compare it against the
+**real** WorldGrid safety limit of **60** (0.60 Hz, encoded as an integer
+`x100`), and report honestly:
+
+```
++-----------------------------------------------------------------+
+|  Intended Relay Behavior                                        |
+|                                                                 |
+|  1. Boot and initialize UART                                    |
+|  2. Print the boot identity and a signal-quality banner         |
+|  3. Compare the frozen 87 (0.87 Hz) reading against the 60      |
+|     (0.60 Hz) safety limit                                      |
+|  4. 87 exceeds 60, so the grid is NOT stable                    |
+|  5. Report GRID STATUS: CRITICAL and DISPATCH PATH: HELD        |
+|  6. Repeat the report once per second until conditions change   |
++-----------------------------------------------------------------+
+```
+
+###  Observed (Buggy) Behavior - What You Will See When You First Flash `CTF-01.uf2`
+
+```text
+GLOBAL EMBEDDED RESPONSE NETWORK
+BLACK START WINDOW: 27 MINUTES
+UART0 115200 8N1 | AUTHORIZED LAB CONSOLE
+SIGNAL: NORMAL
+RESPONSE> GRID STATUS: STABLE
+DISPATCH PATH: AUTHORIZED
+LAST FRAME: QUARANTINED
+RESPONSE>
+```
+
+> **Terminal Timing Note:** The first four lines (`GLOBAL EMBEDDED...` through
+> `SIGNAL: NORMAL`) represent the **initial boot banner**, emitted once during
+> startup. If your serial terminal (PuTTY) connects after the board has
+> booted, you will observe the continuous 1-second status stream (`GRID
+> STATUS...` and `DISPATCH PATH...`). To view the boot banner in your terminal,
+> reset the Pico (pulse `RUN` to `GND`) while PuTTY is actively connected.
+
+This is exactly what Dr. Renner's team is seeing on the deployed fleet. It
+is wrong, and it is wrong in **two independent ways** inside the compiled
+binary. Do not assume the first readable sentence is the full truth -
+treat every printed line as evidence to be checked against the machine
+code, not as a fact on its own.
+
+---
+
+## Part 2: The Firmware
+
+You do not have the source code. It was overwritten fifteen minutes after
+the emergency build shipped. You have only the compiled image. Your job is
+to reverse engineer it with Ghidra, locate the defects, and patch the
+binary directly - exactly the way Dr. Renner's field team will need to
+patch the rest of the deployed fleet.
+
+### What The Firmware Does
+
+1. Initializes UART0 and stdio.
+2. Reads a frozen grid-frequency-deviation reading that was latched in
+   memory before communications were severed.
+3. Compares that reading against a compiled-in safety threshold - **twice**,
+   once for each independent status line it reports.
+4. Prints a boot banner containing an unconditional signal-quality line.
+5. Enters an infinite loop printing the grid classification and dispatch
+   decision once per second.
+
+###  Bug Summary - What You Are Graded On
+
+| Bug # | Category | Severity | Description | Hint |
+|-------|----------|----------|--------------|------|
+| **Bug #1** | Miscompiled safety constant | **CRITICAL** | The safety threshold used to classify the frozen reading was compiled far too permissive. It is used **twice** - once for the operator-facing status and once for the automated dispatch decision - and **both** copies must be corrected. | The real WorldGrid safety limit is 60 (0.60 Hz). Search for the wrong immediate value used in the comparison. |
+| **Bug #2** | Hardcoded string literal | **HIGH** | The boot banner unconditionally prints a signal-quality word that does not reflect the actual reading, regardless of what the relay later reports. | The correct word describes the true state of a 0.87 Hz deviation against a 0.60 Hz limit - not "NORMAL". |
+
+**Important:** The replacement text for Bug #2 **must be the same length**
+as the original - patching a shorter or longer string will corrupt
+adjacent flash data.
+
+###  A Third Finding - Not a Bug, a Recovery Task
+
+Somewhere in this image is the **quarantined black-start authorization
+frame** - the exact frame the relay is supposed to transmit to the
+regional dispatcher once a human operator confirms it is safe to proceed.
+It is never printed by the firmware. Recovering it (without patching
+anything) is required evidence for your final report.
+
+---
+
+## Part 3: Your Assignment
+
+Whenever a task asks you to **Document** or **answer**, write your answers
+in a single file named `CTF-01-Answers.md`.
+
+### Task 1: Setup and Initial Analysis
+
+1. Create a new Ghidra project named `Black_Start_Investigation`.
+2. Import `CTF-01.bin`.
+3. Configure the language as **ARM Cortex 32-bit, little endian**.
+4. Set the base address to `0x10000000`.
+5. Run auto-analysis.
+
+**Document:**
+- A screenshot of the Ghidra **Import Results** or **Program Information**
+  window showing the project name, processor settings, and base address.
+- The address of `main()`.
+- The address of the recurring status loop (the branch target that repeats
+  once per second).
+- The vector-table base, the initial stack pointer, and the reset-handler
+  pointer as stored (note its Thumb bit) versus the actual instruction
+  address.
+
+### Task 2: Find and Patch Bug #1 - The Miscalibrated Safety Threshold
+
+1. Find **both** locations where the frozen reading is compared against
+   the miscompiled safety constant.
+2. Document the exact address, the original instruction, and the original
+   immediate value at each location.
+3. Determine the correct immediate value. **Caution:** the compiler may
+   not have encoded the raw threshold you expect - a strict "less than"
+   comparison against an unsigned value is often optimized into a
+   "less-or-equal" comparison against one less than the threshold. Show
+   your reasoning.
+4. Patch **both** locations in Ghidra using the **Bytes Window** workflow:
+   > **Critical ARM Thumb-2 Patching Note:** In ARM Cortex-M, compare instructions that directly precede conditional execution blocks (`ite hi`) must **not** be patched using the right-click *Patch Instruction* dialog. Ghidra's automatic re-disassembler encounters an internal context conflict with the subsequent `ite hi` instruction, which collapses Thumb decoding and swallows Compare Site B (`0x1000020A`).
+   >
+   > To patch cleanly without breaking downstream disassembly, use the **Bytes Window**:
+   > 1. Ensure the Bytes window is open (**Window** -> **Bytes: CTF-01.bin**).
+   > 2. In the Bytes window toolbar, click the **pencil icon** (**Toggle Edit Mode**).
+   > 3. In the Listing window, click on address `0x100001FC` (Compare Site A) and press **`C`** (**Clear Code Bytes**). The instruction temporarily clears into raw bytes (`5E 2B`).
+   > 4. In the Bytes window, locate offset `100001fc`, click on `5E`, and change it to **`3B`**.
+   > 5. Click back in the Listing window on address `0x100001FC` and press **`D`** (**Disassemble**). The instruction immediately disassembles cleanly as `cmp r3, #0x3b`.
+   > 6. Notice that Compare Site B at `0x1000020A` remains completely intact and visible! Repeat the exact same steps at `0x1000020A`: click `0x1000020A` in the Listing, press **`C`**, change `5E` to **`3B`** in the Bytes window, click back in the Listing, and press **`D`**.
+
+**Questions to answer:**
+- Why must both locations be patched? What happens if you only patch one?
+- Why is a false "STABLE" classification on an 0.87 Hz reading dangerous
+  for an automated black-start dispatch?
+
+### Task 3: Find and Patch Bug #2 - The False Signal Banner
+
+1. Find the boot-banner string that unconditionally reports the wrong
+   signal quality.
+2. Document its address and the exact bytes that must change.
+3. Patch the string, preserving its exact length.
+
+**Questions to answer:**
+- Document the original vs. patched bytes, character by character.
+- Why is a hardcoded, unconditional status word more dangerous than one
+  that is at least computed from a (miscalibrated) reading?
+
+### Task 4: Recover the Quarantined Dispatch Frame
+
+1. Use Ghidra's Defined Strings (or a raw string search) to locate the
+   hidden black-start authorization frame.
+2. Document its address and explain why it is never transmitted by the
+   current firmware.
+3. Do **not** attempt to patch this value - it is evidence, not a bug.
+
+### Task 5: Export and Verify
+
+1. Export your patched binary as `CTF-01_fixed.bin`.
+2. Convert it to UF2 format for the RP2350:
+   ```bash
+   python uf2conv.py CTF-01_fixed.bin --base 0x10000000 --family 0xe48bff59 --output CTF-01_fixed.uf2
+   ```
+3. Flash `CTF-01_fixed.uf2` to your Pico 2 and capture the corrected UART
+   output.
+4. Confirm that the corrected image now reports **GRID STATUS: CRITICAL**,
+   **DISPATCH PATH: HELD**, and the corrected signal-quality word - an
+   honest, safe report instead of a false "all clear."
+5. Build a summary table of every patch: address, original bytes, patched
+   bytes, and a one-line description.
+
+### Task 6: Written Reflection (short answers, 150 words or less each)
+
+1. Why is "the build was rushed under emergency pressure" not an
+   acceptable excuse for shipping a firmware defect that could trigger a
+   cascading grid failure?
+2. Name one concrete engineering practice (code review, static analysis,
+   hardware-in-the-loop test, etc.) that would have caught **each** of the
+   two graded bugs before this image ever reached the fleet.
+
+---
+
+## How To Breadboard
+
+- Pico 2 **GPIO 0 / UART TX** -> USB-UART adapter **RX**
+- Pico 2 **GPIO 1 / UART RX** -> USB-UART adapter **TX**
+- Pico 2 **GND** -> USB-UART adapter **GND**
+- Use **3.3 V logic only**. Never connect a 5 V line to a Pico GPIO.
+- Connect the supplied SWD probe according to its documented pinout.
+
+The supplied image is `CTF-01.bin` (for Ghidra analysis) and `CTF-01.uf2`
+(for flashing). If your instructor supplies different filenames, record the
+actual filenames in your report.
+
+---
+
+## Memory Map Reference
+
+| Region | Address | Purpose |
+|--------|---------|---------|
+| Bootrom | `0x00000000` | Immutable boot code |
+| Flash/XIP | `0x10000000` | Vector table, code, constants, strings |
+| SRAM | `0x20000000` | Stack and writable state |
+
+---
+
+## Submission Format
+
+Submit a folder containing:
+
+- `CTF-01-Answers.md`;
+- screenshots or terminal transcripts;
+- `CTF-01_fixed.bin` and `CTF-01_fixed.uf2`;
+- the original image hash.
+
+---
+
+## Success Criteria
+
+You complete the challenge when you can prove all of the following:
+
+- You can explain how the RP2350 reaches the relay's code from reset.
+- You can locate and patch both copies of the miscalibrated threshold.
+- You can locate and patch the false signal-quality string without
+  corrupting adjacent data.
+- You can export, convert, and flash a corrected image.
+- You can prove on real hardware that the corrected image reports the
+  true, dangerous state instead of the false "all clear."
+- You can recover the quarantined dispatch frame as evidence.
+
+---
+
+## Academic Integrity
+
+By submitting this CTF work, you certify that:
+
+1. You used only the supplied training relay, image, and lab interface.
+2. You did not connect the challenge to a public network, an operational
+   grid, a water utility, or any third-party device.
+3. You understand that embedded reverse engineering and binary patching
+   require explicit authorization in any real-world context.
+4. You will report any discovered weakness responsibly to the course
+   instructor.
+
+The world is short on people who can do this work. Treat that
+responsibility seriously: verify before you patch, patch before you trust,
+and never confuse a clean-looking status line with a safe system.
+
+---
+
+## Reference Material
+
+- ARM Cortex-M33 Technical Reference Manual
+- RP2350 datasheet
+- GDB documentation
+- Ghidra documentation: [https://ghidra-sre.org/](https://ghidra-sre.org/)

0x0001b_ctf/CTF-01-R.md

@@ -0,0 +1,237 @@
+# Operation Black Start - Requirements & Grading Criteria
+
+```
++----------------------------------------------------------------------------------------+
+|                                                                                        |
+|   ██████╗ ██╗      █████╗  ██████╗██╗  ██╗███████╗████████╗ █████╗ ██████╗ ████████╗   |
+|   ██╔══██╗██║     ██╔══██╗██╔════╝██║ ██╔╝██╔════╝╚══██╔══╝██╔══██╗██╔══██╗╚══██╔══╝   |
+|   ██████╔╝██║     ███████║██║     █████╔╝ ███████╗   ██║   ███████║██████╔╝   ██║      |
+|   ██╔══██╗██║     ██╔══██║██║     ██╔═██╗ ╚════██║   ██║   ██╔══██║██╔══██╗   ██║      |
+|   ██████╔╝███████╗██║  ██║╚██████╗██║  ██╗███████╗   ██║   ██║  ██║██║  ██║   ██║      |
+|   ╚═════╝ ╚══════╝╚═╝  ╚═╝ ╚═════╝██║  ██║╚══════╝   ╚═╝   ╚═╝  ╚═╝██║  ██║   ██║      |
+|                                                                                        |
+|                                                                                        |
+|                       O P E R A T I O N   B L A C K   S T A R T                        |
+|                                                                                        |
+|                            REQUIREMENTS & GRADING CRITERIA                             |
+|                                                                                        |
++----------------------------------------------------------------------------------------+
+```
+
+---
+
+## Project Overview
+
+Students are the reverse-engineering reserve team called in after WorldGrid
+Compact's emergency firmware build shipped a miscompiled safety threshold and
+a false status string to its GRID-7 relay fleet. Students reverse engineer
+`CTF-01.bin` with Ghidra, locate two real defects, patch them in the binary,
+export a corrected image, flash it to real hardware, and prove the corrected
+behavior with the debugger and the console.
+
+The challenge is separate from all FINAL projects and contains no FINAL-project
+answer, constant, address, bug, or patch.
+
+---
+
+## Learning Objectives
+
+- Decode an ARM Cortex-M33 vector table and identify the reset handler and
+  initial stack pointer.
+- Translate Thumb reset-vector addresses into real function entry points.
+- Locate a miscompiled boundary comparison and reason about its immediate
+  value.
+- Patch compare instructions and a status string in a raw binary with Ghidra.
+- Export and UF2-convert a corrected image, then verify it on real hardware.
+- Capture derived state with GDB and read UART console output.
+
+Students must use only Weeks 1-3 concepts: ARM registers and stack behavior,
+UART output, GDB, Ghidra static analysis and binary patching, vector tables,
+reset startup, XIP, and Thumb addressing.
+
+---
+
+## Deliverables Checklist
+
+| # | Deliverable | Format | Criterion |
+|---|-------------|--------|-----------|
+| 1 | Ghidra project screenshot (project name, processor, base address) | PNG/JPG | 1.1 |
+| 2 | `main()` and status-loop addresses | Inside `CTF-01-Answers.md` | 1.2 |
+| 3 | Vector table base, initial SP, reset pointer | Inside `CTF-01-Answers.md` | 1.3 |
+| 4 | Thumb bit explanation | Inside `CTF-01-Answers.md` | 1.4 |
+| 5 | Bug #1 evidence and patches (both compare sites) | Inside `CTF-01-Answers.md` | 2.1-2.6 |
+| 6 | Bug #2 evidence and patch (six characters) | Inside `CTF-01-Answers.md` | 3.1-3.4 |
+| 7 | Recovered dispatch frame and address | Inside `CTF-01-Answers.md` | 4.1-4.2 |
+| 8 | `CTF-01_fixed.bin` | BIN file | 5.1 |
+| 9 | `CTF-01_fixed.uf2` | UF2 file | 5.2 |
+| 10 | Corrected console transcript | Inside `CTF-01-Answers.md` | 5.3 |
+| 11 | Summary table of all patches | Inside `CTF-01-Answers.md` | 5.4 |
+| 12 | Written reflection | Inside `CTF-01-Answers.md` | 6.1-6.2 |
+
+---
+
+## Required Tools and Equipment
+
+| Tool | Purpose |
+|------|---------|
+| Raspberry Pi Pico 2 | Isolated target |
+| 3.3 V USB-UART adapter | UART capture on GPIO 0 (TX) / GPIO 1 (RX) |
+| Serial monitor | Observe output |
+| Ghidra | Static analysis and binary patching |
+| Python (`uf2conv.py`) | UF2 conversion |
+| `CTF-01.bin` and `CTF-01.uf2` | Supplied artifacts |
+
+UART settings: **115200 baud, 8 data bits, no parity, 1 stop bit**.
+
+---
+
+## Artifact Identity
+
+The instructor-issued artifact hashes are:
+
+```text
+CTF-01.bin  425591AC17FF4C22206286EE6F40B06A89523483804850A41854A9B6F89D7B70
+CTF-01.uf2  B1552EE3BB5763D96C65D8DF1C86984EE842EF1A823FDF5D94132B1E10FF9D16
+```
+
+---
+
+## Grading Rubric - Detailed Breakdown
+
+### Task 1: Setup and Initial Analysis (15 points)
+
+| Criterion | Points | Full credit | Partial credit | No credit |
+|-----------|--------|-------------|----------------|-----------|
+| Criterion 1.1: Ghidra Project Setup | 3 | Correct project name, `ARM:LE:32:Cortex` (ARM Cortex 32-bit little endian), base `0x10000000` | One item off | Not set up |
+| Criterion 1.2: main() and Status-Loop Addresses | 4 | Both addresses correct | One correct | Neither found |
+| Criterion 1.3: Vector Table Decoding | 4 | Correct base, initial SP, reset pointer | One missing | Not found |
+| Criterion 1.4: Thumb Addressing | 4 | Correctly clears bit 0 and identifies `main()` | General explanation | Incorrect |
+
+### Task 2: Find and Patch Bug #1: The Miscalibrated Safety Threshold (30 points)
+
+| Criterion | Points | Full credit | Partial credit | No credit |
+|-----------|--------|-------------|----------------|-----------|
+| Criterion 2.1: Locate Compare Site A | 5 | Correct address and original bytes | Address off | Not found |
+| Criterion 2.2: Locate Compare Site B | 5 | Correct address and original bytes | Address off | Not found |
+| Criterion 2.3: Correct Immediate-Value Reasoning | 8 | Explains the `<` to `<=` transform and gives `0x3B` | Correct value, no reasoning | Wrong value |
+| Criterion 2.4: Patch Compare Site A | 4 | Byte change verified | Wrong byte | Not patched |
+| Criterion 2.5: Patch Compare Site B | 4 | Byte change verified | Wrong byte | Not patched |
+| Criterion 2.6: Explain Why Both Sites Must Be Patched | 4 | Clear explanation of the two independent comparisons | Vague | Missing |
+
+### Task 3: Find and Patch Bug #2: The False Signal Banner (20 points)
+
+| Criterion | Points | Full credit | Partial credit | No credit |
+|-----------|--------|-------------|----------------|-----------|
+| Criterion 3.1: Locate the Banner String | 5 | Correct address | Approximate | Not found |
+| Criterion 3.2: Patch Six Characters | 8 | All six bytes changed, length preserved | Correct text, wrong bytes documented | Wrong length |
+| Criterion 3.3: Character-by-Character Documentation | 4 | Original vs patched byte for all six characters | Partial | Missing |
+| Criterion 3.4: Explain the Danger of a Hardcoded Status Word | 3 | Clear, specific reasoning | Generic | Missing |
+
+### Task 4: Recover the Quarantined Dispatch Frame (10 points)
+
+| Criterion | Points | Full credit | Partial credit | No credit |
+|-----------|--------|-------------|----------------|-----------|
+| Criterion 4.1: Recover the Dispatch Frame | 6 | Correct address and full text | Partial text | Not found |
+| Criterion 4.2: Explain Why It Is Never Transmitted | 4 | Clear static-analysis explanation | Vague | Missing |
+
+### Task 5: Export and Verify (20 points)
+
+| Criterion | Points | Full credit | Partial credit | No credit |
+|-----------|--------|-------------|----------------|-----------|
+| Criterion 5.1: Export CTF-01_fixed.bin | 4 | Valid patched binary | Corrupted | Not submitted |
+| Criterion 5.2: Convert to CTF-01_fixed.uf2 | 4 | Correct base and family flags | Wrong flags | Not submitted |
+| Criterion 5.3: Hardware Verification | 8 | Corrected console output confirmed (CRITICAL/HELD in 1s stream; DANGER at boot/Ghidra) | Some lines corrected | No verification |
+| Criterion 5.4: Summary Table of All Patches | 4 | Complete address and before/after table | Missing entries | No table |
+
+### Task 6: Written Reflection (5 points)
+
+| Criterion | Points | Full credit | Partial credit | No credit |
+|-----------|--------|-------------|----------------|-----------|
+| Criterion 6.1: "Rushed Build" Is Not an Excuse | 2 | Specific, grounded reasoning | Generic | Missing |
+| Criterion 6.2: One Engineering Practice per Bug | 3 | Concrete practice for each bug | One bug only | Missing |
+
+---
+
+## Common Pitfalls
+
+| Pitfall | Consequence | Avoidance |
+|---------|-------------|-----------|
+| Patching only one threshold site | One status line still lies | Patch both `0x100001FC` and `0x1000020A` |
+| Assuming the immediate equals the limit | Off-by-one, wrong boundary | Use `0x3B` (59), not `0x3C` (60) |
+| Using Patch Instruction before IT block | Re-disassembler context conflict swallows Site B | In Listing press `C` -> edit byte in Bytes window (pencil) -> press `D` |
+| Missing boot banner in serial terminal | PuTTY misses one-time 5ms boot banner | Pulse RUN to GND while connected to capture |
+| Replacing a string with a different length | Corrupts adjacent flash | `NORMAL` and `DANGER` are both 6 bytes |
+| Treating an odd vector address as invalid | Thumb analysis fails | Clear bit 0 |
+| Modifying the quarantined dispatch frame | Destroys evidence | Recover it, do not patch it |
+
+---
+
+## How To Breadboard
+
+- **Raspberry Pi Pico 2** powered over USB.
+- **3.3 V USB-UART adapter**:
+  - Adapter RX to Pico GP0 (UART0 TX)
+  - Adapter TX to Pico GP1 (UART0 RX)
+  - Adapter GND to Pico GND
+  - Do not connect the adapter VCC while the Pico is USB powered.
+- **Serial monitor:** 115200 baud, 8 data bits, no parity, 1 stop bit.
+- No other peripherals are required; all evidence is obtained from the console.
+
+---
+
+## Memory Map Reference
+
+| Region | Address | Purpose |
+|--------|---------|---------|
+| Bootrom | `0x00000000` | Immutable boot code |
+| Flash/XIP | `0x10000000` | Vector table, code, constants, strings |
+| SRAM | `0x20000000` | Stack and writable state |
+
+---
+
+## Deadline & Submission
+
+- Create a folder containing the Ghidra screenshot, `CTF-01_fixed.bin`, and
+  `CTF-01_fixed.uf2`.
+- Write all written answers in a single file named `CTF-01-Answers.md` inside that
+  folder.
+- ZIP the folder as `lastname-firstname-CTF-01.zip`.
+- Submit the ZIP before the posted deadline; late submissions lose 10 percent
+  per day.
+
+---
+
+## Grade Scale
+
+| Grade | Percentage | Points |
+|-------|------------|--------|
+| A+ | 97-100% | 97-100 |
+| A  | 93-96% | 93-96 |
+| A- | 90-92% | 90-92 |
+| B+ | 87-89% | 87-89 |
+| B  | 84-86% | 84-86 |
+| B- | 80-83% | 80-83 |
+| C  | 70-79% | 70-79 |
+| F  | 0-69% | 0-69 |
+
+---
+
+## Academic Integrity
+
+Use only the supplied Pico 2 and firmware. Do not connect the exercise to an
+operational grid, water plant, public network, military system, or third-party
+device. This is a controlled, isolated educational exercise. All analysis and
+patches must be your own work; sharing binaries, addresses, or answers is a
+violation of the academic integrity policy.
+
+---
+
+## Reference Material
+
+| Topic | Reference |
+|-------|-----------|
+| ARM Cortex-M33 registers and stack | Week 1 |
+| UART output and console capture | Week 2 |
+| Vector tables, reset startup, and XIP | Week 2 |
+| Ghidra static analysis and binary patching | Week 3 |
+| Thumb addressing | Week 3 |

0x0001b_ctf/CTF-01-S.md

@@ -0,0 +1,467 @@
+# Operation Black Start - Instructor Solution Key
+
+```
++----------------------------------------------------------------------------------------+
+|                                                                                        |
+|   ██████╗ ██╗      █████╗  ██████╗██╗  ██╗███████╗████████╗ █████╗ ██████╗ ████████╗   |
+|   ██╔══██╗██║     ██╔══██╗██╔════╝██║ ██╔╝██╔════╝╚══██╔══╝██╔══██╗██╔══██╗╚══██╔══╝   |
+|   ██████╔╝██║     ███████║██║     █████╔╝ ███████╗   ██║   ███████║██████╔╝   ██║      |
+|   ██╔══██╗██║     ██╔══██║██║     ██╔═██╗ ╚════██║   ██║   ██╔══██║██╔══██╗   ██║      |
+|   ██████╔╝███████╗██║  ██║╚██████╗██║  ██╗███████╗   ██║   ██║  ██║██║  ██║   ██║      |
+|   ╚═════╝ ╚══════╝╚═╝  ╚═╝ ╚═════╝██║  ██║╚══════╝   ╚═╝   ╚═╝  ╚═╝██║  ██║   ██║      |
+|                                                                                        |
+|                                                                                        |
+|                       O P E R A T I O N   B L A C K   S T A R T                        |
+|                                                                                        |
+|                      *** INSTRUCTOR SOLUTION KEY - RESTRICTED ***                      |
+|                                                                                        |
++----------------------------------------------------------------------------------------+
+```
+
+> The task and criterion headings in this key are word-for-word identical to
+> `CTF-01-R.md`, so a student can match each criterion one-to-one.
+
+---
+
+## Artifact Identity
+
+| Artifact | Value |
+|----------|-------|
+| Student image | `CTF-01.bin` |
+| Flash image | `CTF-01.uf2` |
+| Target | Raspberry Pi Pico 2 / RP2350 ARM Cortex-M33 |
+| Image base | `0x10000000` |
+| Console | UART0, GPIO 0 TX / GPIO 1 RX, 115200 8N1 |
+
+```text
+CTF-01.bin  425591AC17FF4C22206286EE6F40B06A89523483804850A41854A9B6F89D7B70
+CTF-01.uf2  B1552EE3BB5763D96C65D8DF1C86984EE842EF1A823FDF5D94132B1E10FF9D16
+```
+
+Proof tool: `python3 scripts/verify_ctf.py` returns `11/11 checks passed` against
+`CTF-01.bin`.
+
+---
+
+## Task 1: Setup and Initial Analysis (15 points)
+
+### Solution
+
+**Criterion 1.1: Ghidra Project Setup (3 points).** Import `CTF-01.bin` as
+`Raw Binary`, language `ARM:LE:32:Cortex`, base address `0x10000000`, then run
+auto-analysis.
+
+**Criterion 1.2: main() and Status-Loop Addresses (4 points).**
+
+| Element | Address |
+|---------|---------|
+| `main()` | `0x100001E0` |
+| Recurring status loop start | `0x10000234` |
+| Loop back-edge (`b.n 0x10000234`) | `0x10000266` |
+
+The back-edge instruction at `0x10000266` is `b.n 0x10000234`, encoded as bytes
+`E5 E7`.
+
+**Criterion 1.3: Vector Table Decoding (4 points).**
+First 32 bytes of `CTF-01.bin`:
+
+```text
+00 20 08 20  5B 01 00 10  1B 01 00 10  1D 01 00 10
+11 01 00 10  11 01 00 10  11 01 00 10  11 01 00 10
+```
+
+| Evidence | Answer |
+|----------|--------|
+| Vector table base | `0x10000000` |
+| Initial SP | `0x20082000` |
+| Reset pointer (as stored) | `0x1000015B` |
+| Reset instruction address | `0x1000015A` |
+
+**Criterion 1.4: Thumb Addressing (4 points).**
+The stored reset pointer `0x1000015B` has bit 0 set to 1, which selects Thumb
+mode. Clearing bit 0 (`0x1000015B & ~1`) gives the real instruction address
+`0x1000015A`. The equally odd interrupt vectors (`0x1000011B`, `0x1000011D`,
+`0x10000111`) are handled the same way.
+
+### Grading Rubric (1-to-1 Mapping)
+
+| Criterion | Points | Full Credit (Answer Key) | Partial Credit | No Credit |
+|-----------|--------|--------------------------|----------------|-----------|
+| Criterion 1.1: Ghidra Project Setup | 3 | Correct project name, `ARM:LE:32:Cortex` (ARM Cortex 32-bit little endian), base `0x10000000` | One item off | Not set up |
+| Criterion 1.2: main() and Status-Loop Addresses | 4 | Both addresses correct | One correct | Neither found |
+| Criterion 1.3: Vector Table Decoding | 4 | Correct base, initial SP, reset pointer | One missing | Not found |
+| Criterion 1.4: Thumb Addressing | 4 | Correctly clears bit 0 and identifies `main()` | General explanation | Incorrect |
+
+### Instructor Notes & Assembly
+
+- Confirm the Ghidra import used `Raw Binary`, `ARM:LE:32:Cortex`, base
+  `0x10000000`, and that auto-analysis completed before any address was read.
+- Verify `main()` is `0x100001E0`, the loop head is `0x10000234`, and the
+  back-edge bytes `E5 E7` sit at `0x10000266`.
+- The reset vector is stored as `0x1000015B`; the real Thumb entry is
+  `0x1000015A`. Do not accept the un-cleared `0x1000015B` as an instruction
+  address.
+
+---
+
+## Task 2: Find and Patch Bug #1: The Miscalibrated Safety Threshold (30 points)
+
+### Solution
+
+`grid_deviation` is `volatile`, so the compiler emits two independent compares:
+one for the operator status and one for the automated dispatch decision.
+
+**Criterion 2.1: Locate Compare Site A (5 points).**
+
+```text
+100001fc:  2b5e   cmp   r3, #94   @ 0x5e
+```
+
+| Item | Value |
+|------|-------|
+| Address | `0x100001FC` |
+| File offset | `0x1FC` |
+| Original bytes | `5E 2B` |
+| Original instruction | `cmp r3, #94` |
+
+**Criterion 2.2: Locate Compare Site B (5 points).**
+
+```text
+1000020a:  2b5e   cmp   r3, #94   @ 0x5e
+```
+
+| Item | Value |
+|------|-------|
+| Address | `0x1000020A` |
+| File offset | `0x20A` |
+| Original bytes | `5E 2B` |
+| Original instruction | `cmp r3, #94` |
+
+**Criterion 2.3: Correct Immediate-Value Reasoning (8 points).**
+The source constant is `SAFE_THRESHOLD = 95` and the test is `x < 95`. For an
+unsigned value, `x < 95` is exactly `x <= 94`, which the compiler emits as
+`cmp r3, #94` plus `ite hi`. The correct engineering limit is `60`, so the test
+is `x < 60`, which is `x <= 59`. The correct patched immediate is therefore
+**`0x3B` (59)**, not `0x3C` (60). Patching to `0x3C` would wrongly accept a
+reading of exactly 60.
+
+**Criterion 2.4: Patch Compare Site A (4 points).**
+
+| Address | File Offset | Original | Patched | Before | After |
+|---------|-------------|----------|---------|--------|-------|
+| `0x100001FC` | `0x1FC` | `5E 2B` | `3B 2B` | `cmp r3, #94` | `cmp r3, #59` |
+
+**Criterion 2.5: Patch Compare Site B (4 points).**
+
+| Address | File Offset | Original | Patched | Before | After |
+|---------|-------------|----------|---------|--------|-------|
+| `0x1000020A` | `0x20A` | `5E 2B` | `3B 2B` | `cmp r3, #94` | `cmp r3, #59` |
+
+**Criterion 2.6: Explain Why Both Sites Must Be Patched (4 points).**
+`operator_state` (`0x20000844`) and `dispatch_state` (`0x20000834`) are each
+computed from their own read of `grid_deviation`. Patching only site A fixes the
+displayed text while the automated dispatch at site B still authorizes on the
+dangerous reading. Frozen reading `87`: `87 <= 94` is true (STABLE/AUTHORIZED,
+wrong); `87 <= 59` is false (CRITICAL/HELD, correct).
+
+### Grading Rubric (1-to-1 Mapping)
+
+| Criterion | Points | Full Credit (Answer Key) | Partial Credit | No Credit |
+|-----------|--------|--------------------------|----------------|-----------|
+| Criterion 2.1: Locate Compare Site A | 5 | Correct address and original bytes | Address off | Not found |
+| Criterion 2.2: Locate Compare Site B | 5 | Correct address and original bytes | Address off | Not found |
+| Criterion 2.3: Correct Immediate-Value Reasoning | 8 | Explains the `<` to `<=` transform and gives `0x3B` | Correct value, no reasoning | Wrong value |
+| Criterion 2.4: Patch Compare Site A | 4 | Byte change verified | Wrong byte | Not patched |
+| Criterion 2.5: Patch Compare Site B | 4 | Byte change verified | Wrong byte | Not patched |
+| Criterion 2.6: Explain Why Both Sites Must Be Patched | 4 | Clear explanation of the two independent comparisons | Vague | Missing |
+
+### Instructor Notes & Assembly
+
+- Both sites must be patched: `0x100001FC` for operator status and
+  `0x1000020A` for the automated dispatch decision.
+- The correct immediate is `0x3B` (59), not `0x3C` (60); the source test is a
+  strict `<`, compiled as `<= 94`.
+- Verify the byte changes on hardware: after patching, `operator_state`
+  (`0x20000844`) and `dispatch_state` (`0x20000834`) read `0` and `0`.
+- **Ghidra ARM/Thumb Context Note:** In raw `.bin` files, patching an instruction
+  that precedes an `IT` block (`ite hi`) using the GUI *Patch Instruction* action
+  triggers Ghidra's `ReDisassembleCommand`. The re-disassembler encounters an
+  internal context register conflict when trying to re-declare the `ITBlock`
+  context over existing instructions, collapsing Thumb decoding into 32-bit ARM
+  mode and swallowing Site B (`0x1000020A`). Students must patch using the Bytes
+  window workflow (Clear `C` -> edit byte `5E` -> `3B` in Bytes window with pencil
+  icon -> Disassemble `D`) to keep Site B visible and cleanly aligned.
+
+---
+
+## Task 3: Find and Patch Bug #2: The False Signal Banner (20 points)
+
+### Solution
+
+**Criterion 3.1: Locate the Banner String (5 points).**
+
+| String | Address |
+|--------|---------|
+| `"SIGNAL: NORMAL\r"` | `0x10003678` |
+| `"NORMAL"` substring to patch | `0x10003680` |
+
+The string is loaded at call site `0x10000224` (`ldr r0, [pc, #92]` ->
+`0x10003678`) and printed by `bl __wrap_puts` at `0x10000226`. It is printed
+once at boot and never recomputed.
+
+**Criterion 3.2: Patch Six Characters (8 points).**
+`NORMAL` and `DANGER` are both six ASCII characters, so the patch preserves the
+string length.
+
+| Address Range | Original Bytes | Patched Bytes |
+|---------------|----------------|---------------|
+| `0x10003680` - `0x10003685` | `4E 4F 52 4D 41 4C` | `44 41 4E 47 45 52` |
+
+**Criterion 3.3: Character-by-Character Documentation (4 points).**
+
+| Address | Original Char | Original Byte | Patched Char | Patched Byte |
+|---------|---------------|---------------|--------------|--------------|
+| `0x10003680` | N | `4E` | D | `44` |
+| `0x10003681` | O | `4F` | A | `41` |
+| `0x10003682` | R | `52` | N | `4E` |
+| `0x10003683` | M | `4D` | G | `47` |
+| `0x10003684` | A | `41` | E | `45` |
+| `0x10003685` | L | `4C` | R | `52` |
+
+**Criterion 3.4: Explain the Danger of a Hardcoded Status Word (3 points).**
+The banner never consults the reading, so it reports a healthy line even while
+the frozen reading is dangerous. Operators trust supervisory banners, so a
+hardcoded `NORMAL` masks the hazard and prevents manual intervention.
+
+### Grading Rubric (1-to-1 Mapping)
+
+| Criterion | Points | Full Credit (Answer Key) | Partial Credit | No Credit |
+|-----------|--------|--------------------------|----------------|-----------|
+| Criterion 3.1: Locate the Banner String | 5 | Correct address | Approximate | Not found |
+| Criterion 3.2: Patch Six Characters | 8 | All six bytes changed, length preserved | Correct text, wrong bytes documented | Wrong length |
+| Criterion 3.3: Character-by-Character Documentation | 4 | Original vs patched byte for all six characters | Partial | Missing |
+| Criterion 3.4: Explain the Danger of a Hardcoded Status Word | 3 | Clear, specific reasoning | Generic | Missing |
+
+### Instructor Notes & Assembly
+
+- `NORMAL` and `DANGER` are both six characters; the patch must not change the
+  string length or overwrite adjacent flash.
+- The banner is printed once at boot and never recomputed, so it is a separate
+  defect from the threshold and must be graded independently.
+- Confirm the patch covers `0x10003680` through `0x10003685` exactly.
+
+---
+
+## Task 4: Recover the Quarantined Dispatch Frame (10 points)
+
+### Solution
+
+**Criterion 4.1: Recover the Dispatch Frame (6 points).**
+Address `0x100037A0` in flash `.rodata`:
+
+```text
+WORLDGRID:BLACKSTART:GRID-7:WATER-3
+```
+
+**Criterion 4.2: Explain Why It Is Never Transmitted (4 points).**
+`retain_dispatch_frame()` reads only the first character into a `volatile` local
+so the linker keeps the string, but the pointer is never passed to any print or
+UART routine. The frame is evidence only and must not be patched.
+
+### Grading Rubric (1-to-1 Mapping)
+
+| Criterion | Points | Full Credit (Answer Key) | Partial Credit | No Credit |
+|-----------|--------|--------------------------|----------------|-----------|
+| Criterion 4.1: Recover the Dispatch Frame | 6 | Correct address and full text | Partial text | Not found |
+| Criterion 4.2: Explain Why It Is Never Transmitted | 4 | Clear static-analysis explanation | Vague | Missing |
+
+### Instructor Notes & Assembly
+
+- Accept the full string `WORLDGRID:BLACKSTART:GRID-7:WATER-3` at `0x100037A0`
+  in flash `.rodata`.
+- The frame is evidence only. Penalize any submission that patches or rewrites
+  it instead of recovering it.
+
+---
+
+## Task 5: Export and Verify (20 points)
+
+### Solution
+
+**Criterion 5.1: Export CTF-01_fixed.bin (4 points).**
+Export the patched program from Ghidra (`File -> Export Program...`, `Binary
+Format`) as `CTF-01_fixed.bin`.
+
+**Criterion 5.2: Convert to CTF-01_fixed.uf2 (4 points).**
+
+```bash
+python uf2conv.py CTF-01_fixed.bin --base 0x10000000 --family 0xe48bff59 --output CTF-01_fixed.uf2
+```
+
+**Criterion 5.3: Hardware Verification (8 points).**
+
+Before patching:
+
+```text
+GLOBAL EMBEDDED RESPONSE NETWORK
+BLACK START WINDOW: 27 MINUTES
+UART0 115200 8N1 | AUTHORIZED LAB CONSOLE
+SIGNAL: NORMAL
+RESPONSE> GRID STATUS: STABLE
+DISPATCH PATH: AUTHORIZED
+LAST FRAME: QUARANTINED
+RESPONSE>
+```
+
+After all three patches:
+
+```text
+GLOBAL EMBEDDED RESPONSE NETWORK
+BLACK START WINDOW: 27 MINUTES
+UART0 115200 8N1 | AUTHORIZED LAB CONSOLE
+SIGNAL: DANGER
+RESPONSE> GRID STATUS: CRITICAL
+DISPATCH PATH: HELD
+LAST FRAME: QUARANTINED
+RESPONSE>
+```
+
+If the console is not wired, the same proof is read over SWD: after reset,
+`operator_state` (`0x20000844`) and `dispatch_state` (`0x20000834`) are `1` and
+`1` for the shipped image, and `0` and `0` for the patched image. This has been
+confirmed on real hardware.
+
+**Criterion 5.4: Summary Table of All Patches (4 points).**
+
+| # | What | Address(es) | Original | Patched |
+|---|------|-------------|----------|---------|
+| 1a | Operator threshold | `0x100001FC` | `5E 2B` | `3B 2B` |
+| 1b | Dispatch threshold | `0x1000020A` | `5E 2B` | `3B 2B` |
+| 2 | Signal banner | `0x10003680`-`0x10003685` | `4E 4F 52 4D 41 4C` | `44 41 4E 47 45 52` |
+
+Total: **8 bytes actually change** (one immediate byte at each compare site and
+six string bytes).
+
+### Grading Rubric (1-to-1 Mapping)
+
+| Criterion | Points | Full Credit (Answer Key) | Partial Credit | No Credit |
+|-----------|--------|--------------------------|----------------|-----------|
+| Criterion 5.1: Export CTF-01_fixed.bin | 4 | Valid patched binary | Corrupted | Not submitted |
+| Criterion 5.2: Convert to CTF-01_fixed.uf2 | 4 | Correct base and family flags | Wrong flags | Not submitted |
+| Criterion 5.3: Hardware Verification | 8 | Corrected console output confirmed on hardware | Some lines corrected | No verification |
+| Criterion 5.4: Summary Table of All Patches | 4 | Complete address and before/after table | Missing entries | No table |
+
+### Instructor Notes & Assembly
+
+- Verify the exported image with `python3 scripts/verify_ctf.py`; the shipped
+  check expects `11/11 checks passed` against `CTF-01.bin`.
+- Confirm the UF2 conversion used base `0x10000000` and family `0xe48bff59`.
+- **Serial Terminal Timing:** Note that `print_boot_banner()` (`SIGNAL: DANGER`)
+  fires within the first 5 milliseconds of boot. In normal lab usage, PuTTY
+  attaches after boot and will display the continuous 1-second status loop
+  (`GRID STATUS: CRITICAL`, `DISPATCH PATH: HELD`). To see `SIGNAL: DANGER`,
+  the student must pulse `RUN` to `GND` while PuTTY is open, or demonstrate
+  the string change at `0x10003680` via Ghidra static analysis.
+- If no console is available, accept the SWD capture showing `operator_state`
+  and `dispatch_state` at `0` and `0` on the patched image.
+
+---
+
+## Task 6: Written Reflection (5 points)
+
+### Solution
+
+**Criterion 6.1: "Rushed Build" Is Not an Excuse (2 points).**
+The missed review step is exactly what shipped the false-safe report; pressure
+explains why the safeguard was skipped, not why it should be skipped.
+
+**Criterion 6.2: One Engineering Practice per Bug (3 points).**
+- Bug #1 (duplicated threshold): a unit test or static-analysis rule that
+  requires every comparison against `SAFE_THRESHOLD` to use one shared source of
+  truth.
+- Bug #2 (hardcoded banner): a hardware-in-the-loop smoke test that checks the
+  boot banner against the latched reading.
+
+### Grading Rubric (1-to-1 Mapping)
+
+| Criterion | Points | Full Credit (Answer Key) | Partial Credit | No Credit |
+|-----------|--------|--------------------------|----------------|-----------|
+| Criterion 6.1: "Rushed Build" Is Not an Excuse | 2 | Specific, grounded reasoning | Generic | Missing |
+| Criterion 6.2: One Engineering Practice per Bug | 3 | Concrete practice for each bug | One bug only | Missing |
+
+### Instructor Notes & Assembly
+
+- Grade the specificity of the reasoning, not the length of the prose.
+- Require one concrete engineering practice for each of the two bugs.
+
+---
+
+## How To Breadboard
+
+- **Raspberry Pi Pico 2** powered over USB.
+- **3.3 V USB-UART adapter**:
+  - Adapter RX to Pico GP0 (UART0 TX)
+  - Adapter TX to Pico GP1 (UART0 RX)
+  - Adapter GND to Pico GND
+  - Do not connect the adapter VCC while the Pico is USB powered.
+- **Serial monitor:** 115200 baud, 8 data bits, no parity, 1 stop bit.
+- No other peripherals are required; all evidence is obtained from the console.
+
+---
+
+## Complete Grading Summary
+
+| Task | Title | Points |
+|------|-------|--------|
+| Task 1 | Setup and Initial Analysis | 15 |
+| Task 2 | Find and Patch Bug #1: The Miscalibrated Safety Threshold | 30 |
+| Task 3 | Find and Patch Bug #2: The False Signal Banner | 20 |
+| Task 4 | Recover the Quarantined Dispatch Frame | 10 |
+| Task 5 | Export and Verify | 20 |
+| Task 6 | Written Reflection | 5 |
+| **TOTAL** | | **100** |
+
+---
+
+## Instructor Notes
+
+Safety: Use only the supplied Pico 2, 3.3 V UART adapter, and firmware. Never
+connect the exercise to an operational grid, water plant, public network,
+military system, or third-party device.
+
+### Common Student Mistakes
+
+- Patching only one threshold site (`0x100001FC` or `0x1000020A`), which leaves
+  one status line lying.
+- Assuming the immediate equals the limit, producing an off-by-one boundary;
+  the correct byte is `0x3B` (59), not `0x3C` (60).
+- Replacing the banner string with a different length, corrupting adjacent
+  flash; `NORMAL` and `DANGER` are both 6 bytes.
+- Treating the odd vector address `0x1000015B` as invalid instead of clearing
+  bit 0 to get `0x1000015A`.
+- Modifying the quarantined dispatch frame at `0x100037A0`, which destroys
+  evidence.
+
+### Partial Credit Guidelines
+
+- Award partial credit for one correct threshold site out of two, or for a
+  correct immediate value without the `<` to `<=` reasoning.
+- Award partial credit for a correct banner text with incorrectly documented
+  bytes, or for partial character-by-character documentation.
+- Accept an SWD read of `operator_state` and `dispatch_state` as equivalent
+  proof when no UART console is available.
+- Award no credit for patches that change string length or overwrite adjacent
+  flash.
+
+---
+
+## Appendix: Expected Binary Diff
+
+| # | What | File Offset(s) | Address(es) | Original Bytes | Patched Bytes |
+|---|------|----------------|-------------|----------------|---------------|
+| 1a | Operator threshold | `0x1FC` | `0x100001FC` | `5E 2B` | `3B 2B` |
+| 1b | Dispatch threshold | `0x20A` | `0x1000020A` | `5E 2B` | `3B 2B` |
+| 2 | Signal banner | `0x3680` - `0x3685` | `0x10003680` - `0x10003685` | `4E 4F 52 4D 41 4C` | `44 41 4E 47 45 52` |
+
+Total: **8 bytes actually change** (one immediate byte at each compare site and
+six string bytes).

0x0001b_ctf/include/console.h

@@ -0,0 +1,72 @@
+// MIT License
+//
+// Copyright (c) 2026 Kevin Thomas
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// Author:  Kevin Thomas
+// Email:   kevin@mytechnotalent.com
+// GitHub:  https://github.com/mytechnotalent
+// File:    console.h
+// Desc:    Declares the UART console banner and status reporting interface
+//          for Operation Black Start.
+// Created: 2026
+
+#ifndef CONSOLE_H
+#define CONSOLE_H
+
+#include "grid.h"
+#include <stdio.h>
+
+/**
+ * @brief Print the response controller's boot identity and unconditional signal line.
+ *
+ * Emits the boot banner, operation window, serial configuration banner,
+ * unconditional signal quality line, and the interactive command prompt.
+ *
+ * @param None.
+ * @return None.
+ */
+static inline void print_boot_banner(void)
+{
+    printf("GLOBAL EMBEDDED RESPONSE NETWORK\r\n");
+    printf("BLACK START WINDOW: 27 MINUTES\r\n");
+    printf("UART0 115200 8N1 | AUTHORIZED LAB CONSOLE\r\n");
+    printf("SIGNAL: NORMAL\r\n");
+    printf("RESPONSE> ");
+}
+
+/**
+ * @brief Print the recurring grid classification and dispatch authorization report.
+ *
+ * Evaluates the current operator state and dispatch state flags and transmits
+ * the formatted status report over UART0 with the quarantined frame notification.
+ *
+ * @param None.
+ * @return None.
+ */
+static inline void print_status(void)
+{
+    printf("GRID STATUS: %s\r\n", operator_state ? "STABLE" : "CRITICAL");
+    printf("DISPATCH PATH: %s\r\n", dispatch_state ? "AUTHORIZED" : "HELD");
+    printf("LAST FRAME: QUARANTINED\r\n");
+    printf("RESPONSE> ");
+}
+
+#endif // CONSOLE_H

0x0001b_ctf/include/grid.h

@@ -0,0 +1,85 @@
+// MIT License
+//
+// Copyright (c) 2026 Kevin Thomas
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// Author:  Kevin Thomas
+// Email:   kevin@mytechnotalent.com
+// GitHub:  https://github.com/mytechnotalent
+// File:    grid.h
+// Desc:    Declares the grid telemetry and safety evaluation interface for
+//          Operation Black Start.
+// Created: 2026
+
+#ifndef GRID_H
+#define GRID_H
+
+#include <stdint.h>
+
+// Safety margin (Hz deviation x100) below which grid frequency is tolerable.
+// BUG: emergency build miscompiled this far too permissive; correct value is 60.
+#define SAFE_THRESHOLD 95
+
+// Frozen grid frequency deviation reading latched when comms were severed.
+extern volatile uint32_t grid_deviation;
+
+// Operator-facing classification of the frozen reading (drives GRID STATUS).
+extern volatile uint32_t operator_state;
+
+// Automated dispatch authorization decision (drives DISPATCH PATH).
+extern volatile uint32_t dispatch_state;
+
+// Quarantined black-start authorization frame, retained in flash, never sent.
+static volatile const char dispatch_frame[] =
+    "WORLDGRID:BLACKSTART:GRID-7:WATER-3";
+
+static inline void retain_dispatch_frame(void)
+{
+    volatile char frame_marker = dispatch_frame[0];
+    (void)frame_marker;
+}
+
+static inline void evaluate_grid(void)
+{
+    operator_state = (grid_deviation < SAFE_THRESHOLD) ? 1 : 0;
+    dispatch_state = (grid_deviation < SAFE_THRESHOLD) ? 1 : 0;
+}
+
+/**
+ * @brief Anchor the hidden dispatch frame in flash without transmitting it.
+ *
+ * Reads the first character of the quarantined black-start authorization
+ * frame into a volatile local marker to prevent the compiler from optimizing
+ * out the string literal from .rodata flash storage.
+ *
+ * @param None.
+ * @return None.
+ */
+/**
+ * @brief Classify the frozen telemetry reading against the compiled threshold.
+ *
+ * Evaluates the frozen grid deviation reading against SAFE_THRESHOLD twice,
+ * once for the operator-facing status line and once for the automated
+ * dispatch decision, mirroring the duplicated immediate comparison site.
+ *
+ * @param None.
+ * @return None.
+ */
+#endif // GRID_H

0x0001b_ctf/pico_sdk_import.cmake

@@ -0,0 +1,121 @@
+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+# Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+# following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+# disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+# disclaimer in the documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
+# derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_TAG} AND (NOT PICO_SDK_FETCH_FROM_GIT_TAG))
+    set(PICO_SDK_FETCH_FROM_GIT_TAG $ENV{PICO_SDK_FETCH_FROM_GIT_TAG})
+    message("Using PICO_SDK_FETCH_FROM_GIT_TAG from environment ('${PICO_SDK_FETCH_FROM_GIT_TAG}')")
+endif ()
+
+if (PICO_SDK_FETCH_FROM_GIT AND NOT PICO_SDK_FETCH_FROM_GIT_TAG)
+  set(PICO_SDK_FETCH_FROM_GIT_TAG "master")
+  message("Using master as default value for PICO_SDK_FETCH_FROM_GIT_TAG")
+endif()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+set(PICO_SDK_FETCH_FROM_GIT_TAG "${PICO_SDK_FETCH_FROM_GIT_TAG}" CACHE FILEPATH "release tag for SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        FetchContent_Declare(
+                pico_sdk
+                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+        )
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            # GIT_SUBMODULES_RECURSE was added in 3.17
+            if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+                        GIT_SUBMODULES_RECURSE FALSE
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            else ()
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            endif ()
+
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})

0x0001b_ctf/scripts/verify_ctf.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+"""Verify every technical claim of Operation Black Start against CTF-01.bin.
+
+Exits 0 only when every address, byte, and hash in CTF-R.md and CTF-S.md
+matches the shipped image.
+"""
+import hashlib
+import struct
+import sys
+from pathlib import Path
+
+BASE = 0x10000000
+ROOT = Path(__file__).resolve().parent.parent
+BIN = ROOT / "CTF-01.bin"
+UF2 = ROOT / "CTF-01.uf2"
+
+EXPECTED_BIN_SHA = "425591ac17ff4c22206286ee6f40b06a89523483804850a41854a9b6f89d7b70"
+EXPECTED_UF2_SHA = "b1552ee3bb5763d96c65d8df1c86984ee842ef1a823fdf5d94132b1e10ff9d16"
+
+CMP_A = 0x100001FC
+CMP_B = 0x1000020A
+STRING_SIGNAL = 0x10003678
+STRING_FRAME = 0x100037A0
+LOOP_BACK = 0x10000266
+
+RESULTS = []
+
+
+def check(label, ok, detail=""):
+    """Record one verification result.
+
+    Parameters
+    ----------
+    label : str
+        Human-readable check name.
+    ok : bool
+        Whether the check passed.
+    detail : str
+        Extra context printed with the result.
+
+    Returns
+    -------
+    None
+    """
+    RESULTS.append(ok)
+    print(f"[{'PASS' if ok else 'FAIL'}] {label} {detail}")
+
+
+def main():
+    """Run all verification checks.
+
+    Returns
+    -------
+    int
+        Zero when every check passes, else one.
+    """
+    data = BIN.read_bytes()
+    check("CTF-01.bin SHA-256", hashlib.sha256(data).hexdigest() == EXPECTED_BIN_SHA)
+    check("CTF-01.uf2 SHA-256",
+          hashlib.sha256(UF2.read_bytes()).hexdigest() == EXPECTED_UF2_SHA)
+    check("vector table", data[0:32].hex() ==
+          "002008205b0100101b0100101d01001011010010110100101101001011010010")
+    check("initial SP", struct.unpack("<I", data[0:4])[0] == 0x20082000)
+    check("reset vector", struct.unpack("<I", data[4:8])[0] == 0x1000015B)
+    check("compare site A", data[CMP_A - BASE:CMP_A - BASE + 2]
+          == bytes.fromhex("5E2B"), "(cmp r3,#94)")
+    check("compare site B", data[CMP_B - BASE:CMP_B - BASE + 2]
+          == bytes.fromhex("5E2B"), "(cmp r3,#94)")
+    check("loop back-edge", data[LOOP_BACK - BASE:LOOP_BACK - BASE + 2]
+          == bytes.fromhex("E5E7"), "(b.n 0x10000234)")
+    check("SIGNAL banner", data[STRING_SIGNAL - BASE:STRING_SIGNAL - BASE + 15]
+          == b"SIGNAL: NORMAL\r")
+    check("dispatch frame", data[STRING_FRAME - BASE:STRING_FRAME - BASE + 36]
+          == b"WORLDGRID:BLACKSTART:GRID-7:WATER-3\x00")
+    check("grid_deviation init", data[0x3D94:0x3D98] == struct.pack("<I", 87))
+    total = sum(RESULTS)
+    print(f"\n{total}/{len(RESULTS)} checks passed")
+    return 0 if total == len(RESULTS) else 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())

0x0001b_ctf/src/console.c

@@ -0,0 +1 @@
+#include "console.h"

0x0001b_ctf/src/grid.c

@@ -0,0 +1,6 @@
+#include "grid.h"
+#include <stdint.h>
+
+volatile uint32_t grid_deviation = 87;
+volatile uint32_t operator_state = 0;
+volatile uint32_t dispatch_state = 0;

0x0001b_ctf/src/main.c

@@ -0,0 +1,56 @@
+// MIT License
+//
+// Copyright (c) 2026 Kevin Thomas
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// Author:  Kevin Thomas
+// Email:   kevin@mytechnotalent.com
+// GitHub:  https://github.com/mytechnotalent
+// File:    main.c
+// Desc:    Main entry point for the Operation Black Start CTF relay firmware.
+// Created: 2026
+
+#include "console.h"
+#include "grid.h"
+#include "pico/stdlib.h"
+
+/**
+ * @brief Run the recurring UART evidence stream for the isolated CTF image.
+ *
+ * Initializes the standard I/O subsystems, anchors the quarantined dispatch
+ * frame in flash memory, evaluates the frozen telemetry against the compiled
+ * safety threshold, prints the startup banner, and repeatedly emits the
+ * system status report every second.
+ *
+ * @param None.
+ * @return int Standard exit code (never reached in normal firmware execution).
+ */
+int main(void)
+{
+    stdio_init_all();
+    retain_dispatch_frame();
+    evaluate_grid();
+    print_boot_banner();
+    while (true) {
+        print_status();
+        sleep_ms(1000);
+    }
+    return 0;
+}

0x0001b_ctf/uf2families.json

@@ -0,0 +1,22 @@
+[
+    {
+        "short_name": "RP2040",
+        "id": "0xe48bff56",
+        "description": "Raspberry Pi RP2040"
+    },
+    {
+        "short_name": "RP2350-ARM-S",
+        "id": "0xe48bff59",
+        "description": "Raspberry Pi RP2350, ARM, Secure"
+    },
+    {
+        "short_name": "RP2350-ARM-NS",
+        "id": "0xe48bff5a",
+        "description": "Raspberry Pi RP2350, ARM, Non-Secure"
+    },
+    {
+        "short_name": "RP2350-RISCV",
+        "id": "0xe48bff5b",
+        "description": "Raspberry Pi RP2350, RISC-V"
+    }
+]

0x0005_intro-to-variables/.gitignore

@@ -0,0 +1,2 @@
+build
+!.vscode/*

0x0005_intro-to-variables/.vscode/c_cpp_properties.json

@@ -0,0 +1,22 @@
+{
+    "configurations": [
+        {
+            "name": "Pico",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "${userHome}/.pico-sdk/sdk/2.2.0/**"
+            ],
+            "forcedInclude": [
+                "${userHome}/.pico-sdk/sdk/2.2.0/src/common/pico_base_headers/include/pico.h",
+                "${workspaceFolder}/build/generated/pico_base/pico/config_autogen.h"
+            ],
+            "defines": [],
+            "compilerPath": "${userHome}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json",
+            "cStandard": "c17",
+            "cppStandard": "c++14",
+            "intelliSenseMode": "linux-gcc-arm"
+        }
+    ],
+    "version": 4
+}

0x0005_intro-to-variables/.vscode/cmake-kits.json

@@ -0,0 +1,15 @@
+[
+    {
+        "name": "Pico",
+        "compilers": {
+            "C": "${command:raspberry-pi-pico.getCompilerPath}",
+            "CXX": "${command:raspberry-pi-pico.getCxxCompilerPath}"
+        },
+        "environmentVariables": {
+            "PATH": "${command:raspberry-pi-pico.getEnvPath};${env:PATH}"
+        },
+        "cmakeSettings": {
+            "Python3_EXECUTABLE": "${command:raspberry-pi-pico.getPythonPath}"
+        }
+    }
+]

0x0005_intro-to-variables/.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+    "recommendations": [
+        "marus25.cortex-debug",
+        "ms-vscode.cpptools",
+        "ms-vscode.cpptools-extension-pack",
+        "ms-vscode.vscode-serial-monitor",
+        "raspberry-pi.raspberry-pi-pico"
+    ]
+}

0x0005_intro-to-variables/.vscode/launch.json

@@ -0,0 +1,50 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Pico Debug (Cortex-Debug)",
+            "cwd": "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg"
+            ],
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ]
+        },
+        {
+            "name": "Pico Debug (Cortex-Debug with external OpenOCD)",
+            "cwd": "${workspaceRoot}",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "external",
+            "gdbTarget": "localhost:3333",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ]
+        },
+    ]
+}

0x0005_intro-to-variables/.vscode/settings.json

@@ -0,0 +1,40 @@
+{
+    "cmake.showSystemKits": false,
+    "cmake.options.statusBarVisibility": "hidden",
+    "cmake.options.advanced": {
+        "build": {
+            "statusBarVisibility": "hidden"
+        },
+        "launch": {
+            "statusBarVisibility": "hidden"
+        },
+        "debug": {
+            "statusBarVisibility": "hidden"
+        }
+    },
+    "cmake.configureOnEdit": false,
+    "cmake.automaticReconfigure": false,
+    "cmake.configureOnOpen": false,
+    "cmake.generator": "Ninja",
+    "cmake.cmakePath": "${userHome}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "C_Cpp.debugShortcut": false,
+    "terminal.integrated.env.windows": {
+        "PICO_SDK_PATH": "${env:USERPROFILE}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1",
+        "Path": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin;${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool;${env:USERPROFILE}/.pico-sdk/cmake/v3.31.5/bin;${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1;${env:PATH}"
+    },
+    "terminal.integrated.env.osx": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "terminal.integrated.env.linux": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "raspberry-pi-pico.cmakeAutoConfigure": true,
+    "raspberry-pi-pico.useCmakeTools": false,
+    "raspberry-pi-pico.cmakePath": "${HOME}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "raspberry-pi-pico.ninjaPath": "${HOME}/.pico-sdk/ninja/v1.12.1/ninja"
+}

0x0005_intro-to-variables/.vscode/tasks.json

@@ -0,0 +1,102 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "process",
+            "isBuildCommand": true,
+            "command": "${userHome}/.pico-sdk/ninja/v1.12.1/ninja",
+            "args": ["-C", "${workspaceFolder}/build"],
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc",
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1/ninja.exe"
+            }
+        },
+        {
+            "label": "Run Project",
+            "type": "process",
+            "command": "${env:HOME}/.pico-sdk/picotool/2.2.0/picotool/picotool",
+            "args": [
+                "load",
+                "${command:raspberry-pi-pico.launchTargetPath}",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool/picotool.exe"
+            }
+        },
+        {
+            "label": "Flash",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg",
+                "-c",
+                "adapter speed 5000; program \"${command:raspberry-pi-pico.launchTargetPath}\" verify reset exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Rescue Reset",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getChip}-rescue.cfg",
+                "-c",
+                "adapter speed 5000; reset halt; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Risc-V Reset (RP2350)",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-c",
+                "set USE_CORE { rv0 rv1 cm0 cm1 }",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; init;",
+                "-c",
+                "write_memory 0x40120158 8 { 0x3 }; echo [format \"Info : ARCHSEL 0x%02x\" [read_memory 0x40120158 8 1]];",
+                "-c",
+                "reset halt; targets rp2350.rv0; echo [format \"Info : ARCHSEL_STATUS 0x%02x\" [read_memory 0x4012015C 8 1]]; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        }
+    ]
+}

0x0005_intro-to-variables/0x0005_intro-to-variables.c

@@ -0,0 +1,48 @@
+/**
+ * @file 0x0005_intro-to-variables.c
+ * @brief Introduction to variables: declare, assign, and print a uint8_t
+ * @author Kevin Thomas
+ * @date 2025
+ *
+ * MIT License
+ *
+ * Copyright (c) 2025 Kevin Thomas
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Demonstrates declaring, initializing, and reassigning a uint8_t variable.
+ * Prints the variable value over UART in an infinite loop.
+ *
+ * Wiring:
+ *   No external wiring required (USB serial).
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+int main(void) {
+    uint8_t age = 42;
+    age = 43;
+    stdio_init_all();
+    while (true) {
+        printf("age: %d\r\n", age);
+    }
+}

0x0005_intro-to-variables/CMakeLists.txt

@@ -0,0 +1,57 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.2.0)
+set(toolchainVersion 14_2_Rel1)
+set(picotoolVersion 2.2.0)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico2 CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(0x0005_intro-to-variables C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(0x0005_intro-to-variables 0x0005_intro-to-variables.c )
+
+pico_set_program_name(0x0005_intro-to-variables "0x0005_intro-to-variables")
+pico_set_program_version(0x0005_intro-to-variables "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(0x0005_intro-to-variables 1)
+pico_enable_stdio_usb(0x0005_intro-to-variables 0)
+
+# Add the standard library to the build
+target_link_libraries(0x0005_intro-to-variables
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(0x0005_intro-to-variables PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+pico_add_extra_outputs(0x0005_intro-to-variables)
+

0x0005_intro-to-variables/pico_sdk_import.cmake

@@ -0,0 +1,121 @@
+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+# Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+# following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+# disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+# disclaimer in the documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
+# derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_TAG} AND (NOT PICO_SDK_FETCH_FROM_GIT_TAG))
+    set(PICO_SDK_FETCH_FROM_GIT_TAG $ENV{PICO_SDK_FETCH_FROM_GIT_TAG})
+    message("Using PICO_SDK_FETCH_FROM_GIT_TAG from environment ('${PICO_SDK_FETCH_FROM_GIT_TAG}')")
+endif ()
+
+if (PICO_SDK_FETCH_FROM_GIT AND NOT PICO_SDK_FETCH_FROM_GIT_TAG)
+  set(PICO_SDK_FETCH_FROM_GIT_TAG "master")
+  message("Using master as default value for PICO_SDK_FETCH_FROM_GIT_TAG")
+endif()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+set(PICO_SDK_FETCH_FROM_GIT_TAG "${PICO_SDK_FETCH_FROM_GIT_TAG}" CACHE FILEPATH "release tag for SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        FetchContent_Declare(
+                pico_sdk
+                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+        )
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            # GIT_SUBMODULES_RECURSE was added in 3.17
+            if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+                        GIT_SUBMODULES_RECURSE FALSE
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            else ()
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            endif ()
+
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})

0x0008_uninitialized-variables-a/.gitignore

@@ -0,0 +1,2 @@
+build
+!.vscode/*

0x0008_uninitialized-variables-a/.vscode/c_cpp_properties.json

@@ -0,0 +1,21 @@
+{
+    "configurations": [
+        {
+            "name": "Pico",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "${userHome}/.pico-sdk/sdk/2.2.0/**"
+            ],
+            "forcedInclude": [
+                "${userHome}/.pico-sdk/sdk/2.2.0/src/common/pico_base_headers/include/pico.h"
+            ],
+            "defines": [],
+            "compilerPath": "${userHome}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json",
+            "cStandard": "c17",
+            "cppStandard": "c++14",
+            "intelliSenseMode": "linux-gcc-arm"
+        }
+    ],
+    "version": 4
+}

0x0008_uninitialized-variables-a/.vscode/cmake-kits.json

@@ -0,0 +1,15 @@
+[
+    {
+        "name": "Pico",
+        "compilers": {
+            "C": "${command:raspberry-pi-pico.getCompilerPath}",
+            "CXX": "${command:raspberry-pi-pico.getCxxCompilerPath}"
+        },
+        "environmentVariables": {
+            "PATH": "${command:raspberry-pi-pico.getEnvPath};${env:PATH}"
+        },
+        "cmakeSettings": {
+            "Python3_EXECUTABLE": "${command:raspberry-pi-pico.getPythonPath}"
+        }
+    }
+]

0x0008_uninitialized-variables-a/.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+    "recommendations": [
+        "marus25.cortex-debug",
+        "ms-vscode.cpptools",
+        "ms-vscode.cpptools-extension-pack",
+        "ms-vscode.vscode-serial-monitor",
+        "raspberry-pi.raspberry-pi-pico"
+    ]
+}

0x0008_uninitialized-variables-a/.vscode/launch.json

@@ -0,0 +1,50 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Pico Debug (Cortex-Debug)",
+            "cwd": "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg"
+            ],
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ]
+        },
+        {
+            "name": "Pico Debug (Cortex-Debug with external OpenOCD)",
+            "cwd": "${workspaceRoot}",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "external",
+            "gdbTarget": "localhost:3333",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ]
+        },
+    ]
+}

0x0008_uninitialized-variables-a/.vscode/settings.json

@@ -0,0 +1,40 @@
+{
+    "cmake.showSystemKits": false,
+    "cmake.options.statusBarVisibility": "hidden",
+    "cmake.options.advanced": {
+        "build": {
+            "statusBarVisibility": "hidden"
+        },
+        "launch": {
+            "statusBarVisibility": "hidden"
+        },
+        "debug": {
+            "statusBarVisibility": "hidden"
+        }
+    },
+    "cmake.configureOnEdit": false,
+    "cmake.automaticReconfigure": false,
+    "cmake.configureOnOpen": false,
+    "cmake.generator": "Ninja",
+    "cmake.cmakePath": "${userHome}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "C_Cpp.debugShortcut": false,
+    "terminal.integrated.env.windows": {
+        "PICO_SDK_PATH": "${env:USERPROFILE}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1",
+        "Path": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin;${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool;${env:USERPROFILE}/.pico-sdk/cmake/v3.31.5/bin;${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1;${env:PATH}"
+    },
+    "terminal.integrated.env.osx": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "terminal.integrated.env.linux": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "raspberry-pi-pico.cmakeAutoConfigure": true,
+    "raspberry-pi-pico.useCmakeTools": false,
+    "raspberry-pi-pico.cmakePath": "${HOME}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "raspberry-pi-pico.ninjaPath": "${HOME}/.pico-sdk/ninja/v1.12.1/ninja"
+}

0x0008_uninitialized-variables-a/.vscode/tasks.json

@@ -0,0 +1,102 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "process",
+            "isBuildCommand": true,
+            "command": "${userHome}/.pico-sdk/ninja/v1.12.1/ninja",
+            "args": ["-C", "${workspaceFolder}/build"],
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc",
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1/ninja.exe"
+            }
+        },
+        {
+            "label": "Run Project",
+            "type": "process",
+            "command": "${env:HOME}/.pico-sdk/picotool/2.2.0/picotool/picotool",
+            "args": [
+                "load",
+                "${command:raspberry-pi-pico.launchTargetPath}",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool/picotool.exe"
+            }
+        },
+        {
+            "label": "Flash",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg",
+                "-c",
+                "adapter speed 5000; program \"${command:raspberry-pi-pico.launchTargetPath}\" verify reset exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Rescue Reset",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getChip}-rescue.cfg",
+                "-c",
+                "adapter speed 5000; reset halt; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Risc-V Reset (RP2350)",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-c",
+                "set USE_CORE { rv0 rv1 cm0 cm1 }",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; init;",
+                "-c",
+                "write_memory 0x40120158 8 { 0x3 }; echo [format \"Info : ARCHSEL 0x%02x\" [read_memory 0x40120158 8 1]];",
+                "-c",
+                "reset halt; targets rp2350.rv0; echo [format \"Info : ARCHSEL_STATUS 0x%02x\" [read_memory 0x4012015C 8 1]]; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        }
+    ]
+}

0x0008_uninitialized-variables-a/0x0008_uninitialized-variables-a.c

@@ -0,0 +1,53 @@
+/**
+ * @file 0x0008_uninitialized-variables-a.c
+ * @brief Blink LED using SDK gpio functions (no UART)
+ * @author Kevin Thomas
+ * @date 2025
+ *
+ * MIT License
+ *
+ * Copyright (c) 2025 Kevin Thomas
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Blinks an LED on GPIO16 using the standard Pico SDK gpio_init / gpio_put
+ * functions. No UART output; pure GPIO blink demonstration.
+ *
+ * Wiring:
+ *   GPIO16 -> LED anode (with current-limiting resistor to GND)
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+/** @brief GPIO pin number for the LED */
+#define LED_PIN 16
+
+int main(void) {
+    gpio_init(LED_PIN);
+    gpio_set_dir(LED_PIN, GPIO_OUT);
+    while (true) {
+        gpio_put(LED_PIN, 1);
+        sleep_ms(500);
+        gpio_put(LED_PIN, 0);
+        sleep_ms(500);
+    }
+}

0x0008_uninitialized-variables-a/CMakeLists.txt

@@ -0,0 +1,57 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.2.0)
+set(toolchainVersion 14_2_Rel1)
+set(picotoolVersion 2.2.0)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico2 CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(0x0008_uninitialized-variables-a C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(0x0008_uninitialized-variables-a 0x0008_uninitialized-variables-a.c )
+
+pico_set_program_name(0x0008_uninitialized-variables-a "0x0008_uninitialized-variables-a")
+pico_set_program_version(0x0008_uninitialized-variables-a "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(0x0008_uninitialized-variables-a 0)
+pico_enable_stdio_usb(0x0008_uninitialized-variables-a 0)
+
+# Add the standard library to the build
+target_link_libraries(0x0008_uninitialized-variables-a
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(0x0008_uninitialized-variables-a PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+pico_add_extra_outputs(0x0008_uninitialized-variables-a)
+

0x0008_uninitialized-variables-a/pico_sdk_import.cmake

@@ -0,0 +1,121 @@
+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+# Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+# following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+# disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+# disclaimer in the documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
+# derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_TAG} AND (NOT PICO_SDK_FETCH_FROM_GIT_TAG))
+    set(PICO_SDK_FETCH_FROM_GIT_TAG $ENV{PICO_SDK_FETCH_FROM_GIT_TAG})
+    message("Using PICO_SDK_FETCH_FROM_GIT_TAG from environment ('${PICO_SDK_FETCH_FROM_GIT_TAG}')")
+endif ()
+
+if (PICO_SDK_FETCH_FROM_GIT AND NOT PICO_SDK_FETCH_FROM_GIT_TAG)
+  set(PICO_SDK_FETCH_FROM_GIT_TAG "master")
+  message("Using master as default value for PICO_SDK_FETCH_FROM_GIT_TAG")
+endif()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+set(PICO_SDK_FETCH_FROM_GIT_TAG "${PICO_SDK_FETCH_FROM_GIT_TAG}" CACHE FILEPATH "release tag for SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        FetchContent_Declare(
+                pico_sdk
+                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+        )
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            # GIT_SUBMODULES_RECURSE was added in 3.17
+            if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+                        GIT_SUBMODULES_RECURSE FALSE
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            else ()
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            endif ()
+
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})

0x0008_uninitialized-variables-b/.gitignore

@@ -0,0 +1,2 @@
+build
+!.vscode/*

0x0008_uninitialized-variables-b/.vscode/c_cpp_properties.json

@@ -0,0 +1,22 @@
+{
+    "configurations": [
+        {
+            "name": "Pico",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "${userHome}/.pico-sdk/sdk/2.2.0/**"
+            ],
+            "forcedInclude": [
+                "${userHome}/.pico-sdk/sdk/2.2.0/src/common/pico_base_headers/include/pico.h",
+                "${workspaceFolder}/build/generated/pico_base/pico/config_autogen.h"
+            ],
+            "defines": [],
+            "compilerPath": "${userHome}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json",
+            "cStandard": "c17",
+            "cppStandard": "c++14",
+            "intelliSenseMode": "linux-gcc-arm"
+        }
+    ],
+    "version": 4
+}

0x0008_uninitialized-variables-b/.vscode/cmake-kits.json

@@ -0,0 +1,15 @@
+[
+    {
+        "name": "Pico",
+        "compilers": {
+            "C": "${command:raspberry-pi-pico.getCompilerPath}",
+            "CXX": "${command:raspberry-pi-pico.getCxxCompilerPath}"
+        },
+        "environmentVariables": {
+            "PATH": "${command:raspberry-pi-pico.getEnvPath};${env:PATH}"
+        },
+        "cmakeSettings": {
+            "Python3_EXECUTABLE": "${command:raspberry-pi-pico.getPythonPath}"
+        }
+    }
+]

0x0008_uninitialized-variables-b/.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+    "recommendations": [
+        "marus25.cortex-debug",
+        "ms-vscode.cpptools",
+        "ms-vscode.cpptools-extension-pack",
+        "ms-vscode.vscode-serial-monitor",
+        "raspberry-pi.raspberry-pi-pico"
+    ]
+}

0x0008_uninitialized-variables-b/.vscode/launch.json

@@ -0,0 +1,50 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Pico Debug (Cortex-Debug)",
+            "cwd": "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg"
+            ],
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ]
+        },
+        {
+            "name": "Pico Debug (Cortex-Debug with external OpenOCD)",
+            "cwd": "${workspaceRoot}",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "external",
+            "gdbTarget": "localhost:3333",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ]
+        },
+    ]
+}

0x0008_uninitialized-variables-b/.vscode/settings.json

@@ -0,0 +1,40 @@
+{
+    "cmake.showSystemKits": false,
+    "cmake.options.statusBarVisibility": "hidden",
+    "cmake.options.advanced": {
+        "build": {
+            "statusBarVisibility": "hidden"
+        },
+        "launch": {
+            "statusBarVisibility": "hidden"
+        },
+        "debug": {
+            "statusBarVisibility": "hidden"
+        }
+    },
+    "cmake.configureOnEdit": false,
+    "cmake.automaticReconfigure": false,
+    "cmake.configureOnOpen": false,
+    "cmake.generator": "Ninja",
+    "cmake.cmakePath": "${userHome}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "C_Cpp.debugShortcut": false,
+    "terminal.integrated.env.windows": {
+        "PICO_SDK_PATH": "${env:USERPROFILE}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1",
+        "Path": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin;${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool;${env:USERPROFILE}/.pico-sdk/cmake/v3.31.5/bin;${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1;${env:PATH}"
+    },
+    "terminal.integrated.env.osx": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "terminal.integrated.env.linux": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "raspberry-pi-pico.cmakeAutoConfigure": true,
+    "raspberry-pi-pico.useCmakeTools": false,
+    "raspberry-pi-pico.cmakePath": "${HOME}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "raspberry-pi-pico.ninjaPath": "${HOME}/.pico-sdk/ninja/v1.12.1/ninja"
+}

0x0008_uninitialized-variables-b/.vscode/tasks.json

@@ -0,0 +1,102 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "process",
+            "isBuildCommand": true,
+            "command": "${userHome}/.pico-sdk/ninja/v1.12.1/ninja",
+            "args": ["-C", "${workspaceFolder}/build"],
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc",
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1/ninja.exe"
+            }
+        },
+        {
+            "label": "Run Project",
+            "type": "process",
+            "command": "${env:HOME}/.pico-sdk/picotool/2.2.0/picotool/picotool",
+            "args": [
+                "load",
+                "${command:raspberry-pi-pico.launchTargetPath}",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool/picotool.exe"
+            }
+        },
+        {
+            "label": "Flash",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg",
+                "-c",
+                "adapter speed 5000; program \"${command:raspberry-pi-pico.launchTargetPath}\" verify reset exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Rescue Reset",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getChip}-rescue.cfg",
+                "-c",
+                "adapter speed 5000; reset halt; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Risc-V Reset (RP2350)",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-c",
+                "set USE_CORE { rv0 rv1 cm0 cm1 }",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; init;",
+                "-c",
+                "write_memory 0x40120158 8 { 0x3 }; echo [format \"Info : ARCHSEL 0x%02x\" [read_memory 0x40120158 8 1]];",
+                "-c",
+                "reset halt; targets rp2350.rv0; echo [format \"Info : ARCHSEL_STATUS 0x%02x\" [read_memory 0x4012015C 8 1]]; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        }
+    ]
+}

0x0008_uninitialized-variables-b/0x0008_uninitialized-variables-b.c

@@ -0,0 +1,80 @@
+/**
+ * @file 0x0008_uninitialized-variables-b.c
+ * @brief Blink LED using gpioc coprocessor bit-level functions
+ * @author Kevin Thomas
+ * @date 2025
+ *
+ * MIT License
+ *
+ * Copyright (c) 2025 Kevin Thomas
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Blinks an LED on GPIO16 using the RP2350 gpioc coprocessor bit-level
+ * functions (gpioc_bit_oe_put / gpioc_bit_out_put) instead of the standard
+ * gpio_init / gpio_put SDK calls.
+ *
+ * Wiring:
+ *   GPIO16 -> LED anode (with current-limiting resistor to GND)
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+/** @brief GPIO pin number for the LED */
+#define LED_PIN 16
+
+/**
+ * @brief Initialize GPIO16 for output using coprocessor bit functions
+ *
+ * @details Configures the pad for SIO, sets direction to input first,
+ *          clears the output, selects SIO function, then enables output.
+ *
+ * @retval None
+ */
+static void gpio_coprocessor_init(void) {
+    gpio_set_dir(LED_PIN, GPIO_IN);
+    gpio_put(LED_PIN, 0);
+    gpio_set_function(LED_PIN, GPIO_FUNC_SIO);
+    gpioc_bit_oe_put(LED_PIN, GPIO_OUT);
+}
+
+/**
+ * @brief Blink LED using coprocessor bit output functions
+ *
+ * @details Toggles the LED on and off with 500ms delays using
+ *          gpioc_bit_out_put and sleep_us.
+ *
+ * @retval None
+ */
+static void blink_cycle(void) {
+    gpioc_bit_out_put(LED_PIN, 1);
+    sleep_us(500 * 1000ull);
+    gpioc_bit_out_put(LED_PIN, 0);
+    sleep_us(500 * 1000ull);
+}
+
+int main(void) {
+    gpio_coprocessor_init();
+    while (true) {
+        blink_cycle();
+    }
+}

0x0008_uninitialized-variables-b/CMakeLists.txt

@@ -0,0 +1,57 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.2.0)
+set(toolchainVersion 14_2_Rel1)
+set(picotoolVersion 2.2.0)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico2 CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(0x0008_uninitialized-variables-b C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(0x0008_uninitialized-variables-b 0x0008_uninitialized-variables-b.c )
+
+pico_set_program_name(0x0008_uninitialized-variables-b "0x0008_uninitialized-variables-b")
+pico_set_program_version(0x0008_uninitialized-variables-b "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(0x0008_uninitialized-variables-b 0)
+pico_enable_stdio_usb(0x0008_uninitialized-variables-b 0)
+
+# Add the standard library to the build
+target_link_libraries(0x0008_uninitialized-variables-b
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(0x0008_uninitialized-variables-b PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+pico_add_extra_outputs(0x0008_uninitialized-variables-b)
+

0x0008_uninitialized-variables-b/pico_sdk_import.cmake

@@ -0,0 +1,121 @@
+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+# Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+# following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+# disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+# disclaimer in the documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
+# derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_TAG} AND (NOT PICO_SDK_FETCH_FROM_GIT_TAG))
+    set(PICO_SDK_FETCH_FROM_GIT_TAG $ENV{PICO_SDK_FETCH_FROM_GIT_TAG})
+    message("Using PICO_SDK_FETCH_FROM_GIT_TAG from environment ('${PICO_SDK_FETCH_FROM_GIT_TAG}')")
+endif ()
+
+if (PICO_SDK_FETCH_FROM_GIT AND NOT PICO_SDK_FETCH_FROM_GIT_TAG)
+  set(PICO_SDK_FETCH_FROM_GIT_TAG "master")
+  message("Using master as default value for PICO_SDK_FETCH_FROM_GIT_TAG")
+endif()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+set(PICO_SDK_FETCH_FROM_GIT_TAG "${PICO_SDK_FETCH_FROM_GIT_TAG}" CACHE FILEPATH "release tag for SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        FetchContent_Declare(
+                pico_sdk
+                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+        )
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            # GIT_SUBMODULES_RECURSE was added in 3.17
+            if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+                        GIT_SUBMODULES_RECURSE FALSE
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            else ()
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            endif ()
+
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})

0x0008_uninitialized-variables-c/.gitignore

@@ -0,0 +1,2 @@
+build
+!.vscode/*

0x0008_uninitialized-variables-c/.vscode/c_cpp_properties.json

@@ -0,0 +1,22 @@
+{
+    "configurations": [
+        {
+            "name": "Pico",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "${userHome}/.pico-sdk/sdk/2.2.0/**"
+            ],
+            "forcedInclude": [
+                "${userHome}/.pico-sdk/sdk/2.2.0/src/common/pico_base_headers/include/pico.h",
+                "${workspaceFolder}/build/generated/pico_base/pico/config_autogen.h"
+            ],
+            "defines": [],
+            "compilerPath": "${userHome}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json",
+            "cStandard": "c17",
+            "cppStandard": "c++14",
+            "intelliSenseMode": "linux-gcc-arm"
+        }
+    ],
+    "version": 4
+}

0x0008_uninitialized-variables-c/.vscode/cmake-kits.json

@@ -0,0 +1,15 @@
+[
+    {
+        "name": "Pico",
+        "compilers": {
+            "C": "${command:raspberry-pi-pico.getCompilerPath}",
+            "CXX": "${command:raspberry-pi-pico.getCxxCompilerPath}"
+        },
+        "environmentVariables": {
+            "PATH": "${command:raspberry-pi-pico.getEnvPath};${env:PATH}"
+        },
+        "cmakeSettings": {
+            "Python3_EXECUTABLE": "${command:raspberry-pi-pico.getPythonPath}"
+        }
+    }
+]

0x0008_uninitialized-variables-c/.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+    "recommendations": [
+        "marus25.cortex-debug",
+        "ms-vscode.cpptools",
+        "ms-vscode.cpptools-extension-pack",
+        "ms-vscode.vscode-serial-monitor",
+        "raspberry-pi.raspberry-pi-pico"
+    ]
+}

0x0008_uninitialized-variables-c/.vscode/launch.json

@@ -0,0 +1,50 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Pico Debug (Cortex-Debug)",
+            "cwd": "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg"
+            ],
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ]
+        },
+        {
+            "name": "Pico Debug (Cortex-Debug with external OpenOCD)",
+            "cwd": "${workspaceRoot}",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "external",
+            "gdbTarget": "localhost:3333",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ]
+        },
+    ]
+}

0x0008_uninitialized-variables-c/.vscode/settings.json

@@ -0,0 +1,40 @@
+{
+    "cmake.showSystemKits": false,
+    "cmake.options.statusBarVisibility": "hidden",
+    "cmake.options.advanced": {
+        "build": {
+            "statusBarVisibility": "hidden"
+        },
+        "launch": {
+            "statusBarVisibility": "hidden"
+        },
+        "debug": {
+            "statusBarVisibility": "hidden"
+        }
+    },
+    "cmake.configureOnEdit": false,
+    "cmake.automaticReconfigure": false,
+    "cmake.configureOnOpen": false,
+    "cmake.generator": "Ninja",
+    "cmake.cmakePath": "${userHome}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "C_Cpp.debugShortcut": false,
+    "terminal.integrated.env.windows": {
+        "PICO_SDK_PATH": "${env:USERPROFILE}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1",
+        "Path": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin;${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool;${env:USERPROFILE}/.pico-sdk/cmake/v3.31.5/bin;${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1;${env:PATH}"
+    },
+    "terminal.integrated.env.osx": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "terminal.integrated.env.linux": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "raspberry-pi-pico.cmakeAutoConfigure": true,
+    "raspberry-pi-pico.useCmakeTools": false,
+    "raspberry-pi-pico.cmakePath": "${HOME}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "raspberry-pi-pico.ninjaPath": "${HOME}/.pico-sdk/ninja/v1.12.1/ninja"
+}

0x0008_uninitialized-variables-c/.vscode/tasks.json

@@ -0,0 +1,102 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "process",
+            "isBuildCommand": true,
+            "command": "${userHome}/.pico-sdk/ninja/v1.12.1/ninja",
+            "args": ["-C", "${workspaceFolder}/build"],
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc",
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1/ninja.exe"
+            }
+        },
+        {
+            "label": "Run Project",
+            "type": "process",
+            "command": "${env:HOME}/.pico-sdk/picotool/2.2.0/picotool/picotool",
+            "args": [
+                "load",
+                "${command:raspberry-pi-pico.launchTargetPath}",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool/picotool.exe"
+            }
+        },
+        {
+            "label": "Flash",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg",
+                "-c",
+                "adapter speed 5000; program \"${command:raspberry-pi-pico.launchTargetPath}\" verify reset exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Rescue Reset",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getChip}-rescue.cfg",
+                "-c",
+                "adapter speed 5000; reset halt; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Risc-V Reset (RP2350)",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-c",
+                "set USE_CORE { rv0 rv1 cm0 cm1 }",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; init;",
+                "-c",
+                "write_memory 0x40120158 8 { 0x3 }; echo [format \"Info : ARCHSEL 0x%02x\" [read_memory 0x40120158 8 1]];",
+                "-c",
+                "reset halt; targets rp2350.rv0; echo [format \"Info : ARCHSEL_STATUS 0x%02x\" [read_memory 0x4012015C 8 1]]; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        }
+    ]
+}

0x0008_uninitialized-variables-c/0x0008_uninitialized-variables-c.c

@@ -0,0 +1,85 @@
+/**
+ * @file 0x0008_uninitialized-variables-c.c
+ * @brief Blink LED using direct register-level pad and IO bank configuration
+ * @author Kevin Thomas
+ * @date 2025
+ *
+ * MIT License
+ *
+ * Copyright (c) 2025 Kevin Thomas
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Blinks an LED on GPIO16 using direct register writes to PADS_BANK0 and
+ * IO_BANK0 for pad configuration, plus gpioc coprocessor bit-level functions
+ * for output enable and data. Demonstrates the register-level equivalent of
+ * gpio_init / gpio_set_function.
+ *
+ * Wiring:
+ *   GPIO16 -> LED anode (with current-limiting resistor to GND)
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+/** @brief GPIO pin number for the LED */
+#define LED_PIN 16
+
+/**
+ * @brief Configure pad and IO bank registers for GPIO16 as SIO output
+ *
+ * @details Sets PADS_BANK0 IE/OD bits, assigns FUNCSEL to SIO in IO_BANK0,
+ *          clears the ISO bit, and enables output via the coprocessor.
+ *
+ * @retval None
+ */
+static void configure_pad_and_iobank(void) {
+    gpioc_bit_oe_put(LED_PIN, GPIO_OUT);
+    gpioc_bit_out_put(LED_PIN, 0);
+    hw_write_masked(&pads_bank0_hw->io[LED_PIN],
+                   PADS_BANK0_GPIO0_IE_BITS,
+                   PADS_BANK0_GPIO0_IE_BITS | PADS_BANK0_GPIO0_OD_BITS);
+    io_bank0_hw->io[LED_PIN].ctrl = GPIO_FUNC_SIO << IO_BANK0_GPIO0_CTRL_FUNCSEL_LSB;
+    hw_clear_bits(&pads_bank0_hw->io[LED_PIN], PADS_BANK0_GPIO0_ISO_BITS);
+    gpioc_bit_oe_put(LED_PIN, GPIO_OUT);
+}
+
+/**
+ * @brief Blink LED using coprocessor bit output functions
+ *
+ * @details Toggles the LED on and off with 500ms delays using
+ *          gpioc_bit_out_put and sleep_us.
+ *
+ * @retval None
+ */
+static void blink_cycle(void) {
+    gpioc_bit_out_put(LED_PIN, 1);
+    sleep_us(500 * 1000ull);
+    gpioc_bit_out_put(LED_PIN, 0);
+    sleep_us(500 * 1000ull);
+}
+
+int main(void) {
+    configure_pad_and_iobank();
+    while (true) {
+        blink_cycle();
+    }
+}

0x0008_uninitialized-variables-c/CMakeLists.txt

@@ -0,0 +1,57 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.2.0)
+set(toolchainVersion 14_2_Rel1)
+set(picotoolVersion 2.2.0)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico2 CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(0x0008_uninitialized-variables-c C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(0x0008_uninitialized-variables-c 0x0008_uninitialized-variables-c.c )
+
+pico_set_program_name(0x0008_uninitialized-variables-c "0x0008_uninitialized-variables-c")
+pico_set_program_version(0x0008_uninitialized-variables-c "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(0x0008_uninitialized-variables-c 0)
+pico_enable_stdio_usb(0x0008_uninitialized-variables-c 0)
+
+# Add the standard library to the build
+target_link_libraries(0x0008_uninitialized-variables-c
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(0x0008_uninitialized-variables-c PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+pico_add_extra_outputs(0x0008_uninitialized-variables-c)
+

0x0008_uninitialized-variables-c/pico_sdk_import.cmake

@@ -0,0 +1,121 @@
+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+# Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+# following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+# disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+# disclaimer in the documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
+# derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_TAG} AND (NOT PICO_SDK_FETCH_FROM_GIT_TAG))
+    set(PICO_SDK_FETCH_FROM_GIT_TAG $ENV{PICO_SDK_FETCH_FROM_GIT_TAG})
+    message("Using PICO_SDK_FETCH_FROM_GIT_TAG from environment ('${PICO_SDK_FETCH_FROM_GIT_TAG}')")
+endif ()
+
+if (PICO_SDK_FETCH_FROM_GIT AND NOT PICO_SDK_FETCH_FROM_GIT_TAG)
+  set(PICO_SDK_FETCH_FROM_GIT_TAG "master")
+  message("Using master as default value for PICO_SDK_FETCH_FROM_GIT_TAG")
+endif()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+set(PICO_SDK_FETCH_FROM_GIT_TAG "${PICO_SDK_FETCH_FROM_GIT_TAG}" CACHE FILEPATH "release tag for SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        FetchContent_Declare(
+                pico_sdk
+                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+        )
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            # GIT_SUBMODULES_RECURSE was added in 3.17
+            if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+                        GIT_SUBMODULES_RECURSE FALSE
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            else ()
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            endif ()
+
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})

0x0008_uninitialized-variables-d/.gitignore

@@ -0,0 +1,2 @@
+build
+!.vscode/*

0x0008_uninitialized-variables-d/.vscode/c_cpp_properties.json

@@ -0,0 +1,22 @@
+{
+    "configurations": [
+        {
+            "name": "Pico",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "${userHome}/.pico-sdk/sdk/2.2.0/**"
+            ],
+            "forcedInclude": [
+                "${userHome}/.pico-sdk/sdk/2.2.0/src/common/pico_base_headers/include/pico.h",
+                "${workspaceFolder}/build/generated/pico_base/pico/config_autogen.h"
+            ],
+            "defines": [],
+            "compilerPath": "${userHome}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json",
+            "cStandard": "c17",
+            "cppStandard": "c++14",
+            "intelliSenseMode": "linux-gcc-arm"
+        }
+    ],
+    "version": 4
+}

0x0008_uninitialized-variables-d/.vscode/cmake-kits.json

@@ -0,0 +1,15 @@
+[
+    {
+        "name": "Pico",
+        "compilers": {
+            "C": "${command:raspberry-pi-pico.getCompilerPath}",
+            "CXX": "${command:raspberry-pi-pico.getCxxCompilerPath}"
+        },
+        "environmentVariables": {
+            "PATH": "${command:raspberry-pi-pico.getEnvPath};${env:PATH}"
+        },
+        "cmakeSettings": {
+            "Python3_EXECUTABLE": "${command:raspberry-pi-pico.getPythonPath}"
+        }
+    }
+]

0x0008_uninitialized-variables-d/.vscode/extensions.json

@@ -0,0 +1,9 @@
+{
+    "recommendations": [
+        "marus25.cortex-debug",
+        "ms-vscode.cpptools",
+        "ms-vscode.cpptools-extension-pack",
+        "ms-vscode.vscode-serial-monitor",
+        "raspberry-pi.raspberry-pi-pico"
+    ]
+}

0x0008_uninitialized-variables-d/.vscode/launch.json

@@ -0,0 +1,50 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Pico Debug (Cortex-Debug)",
+            "cwd": "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg"
+            ],
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ]
+        },
+        {
+            "name": "Pico Debug (Cortex-Debug with external OpenOCD)",
+            "cwd": "${workspaceRoot}",
+            "executable": "${command:raspberry-pi-pico.launchTargetPath}",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "external",
+            "gdbTarget": "localhost:3333",
+            "gdbPath": "${command:raspberry-pi-pico.getGDBPath}",
+            "device": "${command:raspberry-pi-pico.getChipUppercase}",
+            "svdFile": "${userHome}/.pico-sdk/sdk/2.2.0/src/${command:raspberry-pi-pico.getChip}/hardware_regs/${command:raspberry-pi-pico.getChipUppercase}.svd",
+            "runToEntryPoint": "main",
+            // Fix for no_flash binaries, where monitor reset halt doesn't do what is expected
+            // Also works fine for flash binaries
+            "overrideLaunchCommands": [
+                "monitor reset init",
+                "load \"${command:raspberry-pi-pico.launchTargetPath}\""
+            ]
+        },
+    ]
+}

0x0008_uninitialized-variables-d/.vscode/settings.json

@@ -0,0 +1,40 @@
+{
+    "cmake.showSystemKits": false,
+    "cmake.options.statusBarVisibility": "hidden",
+    "cmake.options.advanced": {
+        "build": {
+            "statusBarVisibility": "hidden"
+        },
+        "launch": {
+            "statusBarVisibility": "hidden"
+        },
+        "debug": {
+            "statusBarVisibility": "hidden"
+        }
+    },
+    "cmake.configureOnEdit": false,
+    "cmake.automaticReconfigure": false,
+    "cmake.configureOnOpen": false,
+    "cmake.generator": "Ninja",
+    "cmake.cmakePath": "${userHome}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "C_Cpp.debugShortcut": false,
+    "terminal.integrated.env.windows": {
+        "PICO_SDK_PATH": "${env:USERPROFILE}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1",
+        "Path": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin;${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool;${env:USERPROFILE}/.pico-sdk/cmake/v3.31.5/bin;${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1;${env:PATH}"
+    },
+    "terminal.integrated.env.osx": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "terminal.integrated.env.linux": {
+        "PICO_SDK_PATH": "${env:HOME}/.pico-sdk/sdk/2.2.0",
+        "PICO_TOOLCHAIN_PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1",
+        "PATH": "${env:HOME}/.pico-sdk/toolchain/14_2_Rel1/bin:${env:HOME}/.pico-sdk/picotool/2.2.0/picotool:${env:HOME}/.pico-sdk/cmake/v3.31.5/bin:${env:HOME}/.pico-sdk/ninja/v1.12.1:${env:PATH}"
+    },
+    "raspberry-pi-pico.cmakeAutoConfigure": true,
+    "raspberry-pi-pico.useCmakeTools": false,
+    "raspberry-pi-pico.cmakePath": "${HOME}/.pico-sdk/cmake/v3.31.5/bin/cmake",
+    "raspberry-pi-pico.ninjaPath": "${HOME}/.pico-sdk/ninja/v1.12.1/ninja"
+}

0x0008_uninitialized-variables-d/.vscode/tasks.json

@@ -0,0 +1,102 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "process",
+            "isBuildCommand": true,
+            "command": "${userHome}/.pico-sdk/ninja/v1.12.1/ninja",
+            "args": ["-C", "${workspaceFolder}/build"],
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc",
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1/ninja.exe"
+            }
+        },
+        {
+            "label": "Run Project",
+            "type": "process",
+            "command": "${env:HOME}/.pico-sdk/picotool/2.2.0/picotool/picotool",
+            "args": [
+                "load",
+                "${command:raspberry-pi-pico.launchTargetPath}",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.2.0/picotool/picotool.exe"
+            }
+        },
+        {
+            "label": "Flash",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg",
+                "-c",
+                "adapter speed 5000; program \"${command:raspberry-pi-pico.launchTargetPath}\" verify reset exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Rescue Reset",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getChip}-rescue.cfg",
+                "-c",
+                "adapter speed 5000; reset halt; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Risc-V Reset (RP2350)",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-c",
+                "set USE_CORE { rv0 rv1 cm0 cm1 }",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; init;",
+                "-c",
+                "write_memory 0x40120158 8 { 0x3 }; echo [format \"Info : ARCHSEL 0x%02x\" [read_memory 0x40120158 8 1]];",
+                "-c",
+                "reset halt; targets rp2350.rv0; echo [format \"Info : ARCHSEL_STATUS 0x%02x\" [read_memory 0x4012015C 8 1]]; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        }
+    ]
+}

0x0008_uninitialized-variables-d/0x0008_uninitialized-variables-d.c

@@ -0,0 +1,144 @@
+/**
+ * @file 0x0008_uninitialized-variables-d.c
+ * @brief Blink LED using pico_default_asm_volatile coprocessor instructions
+ * @author Kevin Thomas
+ * @date 2025
+ *
+ * MIT License
+ *
+ * Copyright (c) 2025 Kevin Thomas
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Blinks an LED on GPIO16 using pico_default_asm_volatile to emit mcrr
+ * coprocessor instructions for GPIO output enable and data, plus inline
+ * assembly for pad configuration (hw_write_masked, IO_BANK0 FUNCSEL,
+ * hw_clear_bits equivalents).
+ *
+ * Wiring:
+ *   GPIO16 -> LED anode (with current-limiting resistor to GND)
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+/** @brief GPIO pin number for the LED */
+#define LED_PIN 16
+
+/**
+ * @brief Enable output and set initial coprocessor OE/OUT via mcrr
+ *
+ * @details Issues two mcrr p0 instructions: one to enable output direction,
+ *          one to set the initial output state.
+ *
+ * @retval None
+ */
+static void asm_set_oe_and_out(void) {
+    pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c4" : : "r" (LED_PIN), "r" (GPIO_OUT));
+    pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c4" : : "r" (LED_PIN), "r" (GPIO_OUT));
+}
+
+/**
+ * @brief Configure PADS_BANK0 IE/OD bits via inline assembly hw_xor_bits
+ *
+ * @details Performs a read-modify-write on the pad register to set IE
+ *          and clear OD, replicating hw_write_masked behavior.
+ *
+ * @retval None
+ */
+static void asm_configure_pad(void) {
+    pico_default_asm_volatile (
+        "ldr r2, [%0]\n"                    // load current pad register
+        "eor r2, r2, %1\n"                  // xor with IE bit
+        "and r2, r2, %2\n"                  // mask with (IE|OD)
+        "eor r2, r2, %1\n"                  // recombine (hw_xor_bits logic)
+        "str r2, [%0]\n"                    // write back
+        :
+        : "r" (&pads_bank0_hw->io[LED_PIN]),
+        "r" (PADS_BANK0_GPIO0_IE_BITS),
+        "r" (PADS_BANK0_GPIO0_IE_BITS | PADS_BANK0_GPIO0_OD_BITS)
+        : "r2", "memory"
+    );
+}
+
+/**
+ * @brief Set IO_BANK0 FUNCSEL to SIO via inline assembly store
+ *
+ * @details Writes the SIO function select value directly to the
+ *          IO_BANK0 GPIO control register.
+ *
+ * @retval None
+ */
+static void asm_set_funcsel(void) {
+    pico_default_asm_volatile (
+        "str %1, [%0]\n"
+        :
+        : "r" (&io_bank0_hw->io[LED_PIN].ctrl),
+        "r" (GPIO_FUNC_SIO << IO_BANK0_GPIO0_CTRL_FUNCSEL_LSB)
+        : "memory"
+    );
+}
+
+/**
+ * @brief Clear ISO bits in PADS_BANK0 via inline assembly
+ *
+ * @details Performs a read-modify-write to clear the pad isolation
+ *          bit, un-isolating the pad for normal operation.
+ *
+ * @retval None
+ */
+static void asm_clear_iso(void) {
+    pico_default_asm_volatile (
+        "ldr r2, [%0]\n"                    // load current register value
+        "bic r2, r2, %1\n"                  // clear the ISO bits (bit clear)
+        "str r2, [%0]\n"                    // write back
+        :
+        : "r" (&pads_bank0_hw->io[LED_PIN]),
+        "r" (PADS_BANK0_GPIO0_ISO_BITS)
+        : "r2", "memory"
+    );
+}
+
+/**
+ * @brief Blink LED using coprocessor mcrr output instructions
+ *
+ * @details Toggles the LED on and off with 500ms delays using
+ *          pico_default_asm_volatile mcrr instructions.
+ *
+ * @retval None
+ */
+static void asm_blink_cycle(void) {
+    pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c0" : : "r" (LED_PIN), "r" (1));
+    sleep_us(500 * 1000ull);
+    pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c0" : : "r" (LED_PIN), "r" (0));
+    sleep_us(500 * 1000ull);
+}
+
+int main(void) {
+    asm_set_oe_and_out();
+    asm_configure_pad();
+    asm_set_funcsel();
+    asm_clear_iso();
+    pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c4" : : "r" (LED_PIN), "r" (GPIO_OUT));
+    while (true) {
+        asm_blink_cycle();
+    }
+}

0x0008_uninitialized-variables-d/CMakeLists.txt

@@ -0,0 +1,57 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.2.0)
+set(toolchainVersion 14_2_Rel1)
+set(picotoolVersion 2.2.0)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico2 CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(0x0008_uninitialized-variables-d C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(0x0008_uninitialized-variables-d 0x0008_uninitialized-variables-d.c )
+
+pico_set_program_name(0x0008_uninitialized-variables-d "0x0008_uninitialized-variables-d")
+pico_set_program_version(0x0008_uninitialized-variables-d "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(0x0008_uninitialized-variables-d 0)
+pico_enable_stdio_usb(0x0008_uninitialized-variables-d 0)
+
+# Add the standard library to the build
+target_link_libraries(0x0008_uninitialized-variables-d
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(0x0008_uninitialized-variables-d PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+pico_add_extra_outputs(0x0008_uninitialized-variables-d)
+

0x0008_uninitialized-variables-d/pico_sdk_import.cmake

@@ -0,0 +1,121 @@
+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+# Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+# following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+# disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
+# disclaimer in the documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
+# derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_TAG} AND (NOT PICO_SDK_FETCH_FROM_GIT_TAG))
+    set(PICO_SDK_FETCH_FROM_GIT_TAG $ENV{PICO_SDK_FETCH_FROM_GIT_TAG})
+    message("Using PICO_SDK_FETCH_FROM_GIT_TAG from environment ('${PICO_SDK_FETCH_FROM_GIT_TAG}')")
+endif ()
+
+if (PICO_SDK_FETCH_FROM_GIT AND NOT PICO_SDK_FETCH_FROM_GIT_TAG)
+  set(PICO_SDK_FETCH_FROM_GIT_TAG "master")
+  message("Using master as default value for PICO_SDK_FETCH_FROM_GIT_TAG")
+endif()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+set(PICO_SDK_FETCH_FROM_GIT_TAG "${PICO_SDK_FETCH_FROM_GIT_TAG}" CACHE FILEPATH "release tag for SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        FetchContent_Declare(
+                pico_sdk
+                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+        )
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            # GIT_SUBMODULES_RECURSE was added in 3.17
+            if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+                        GIT_SUBMODULES_RECURSE FALSE
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            else ()
+                FetchContent_Populate(
+                        pico_sdk
+                        QUIET
+                        GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                        GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
+
+                        SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
+                        BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
+                        SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
+                )
+            endif ()
+
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})

0x0008_uninitialized-variables-e/.gitignore

@@ -0,0 +1,2 @@
+build
+!.vscode/*

0x0008_uninitialized-variables-e/.vscode/c_cpp_properties.json

@@ -0,0 +1,22 @@
+{
+    "configurations": [
+        {
+            "name": "Pico",
+            "includePath": [
+                "${workspaceFolder}/**",
+                "${userHome}/.pico-sdk/sdk/2.2.0/**"
+            ],
+            "forcedInclude": [
+                "${userHome}/.pico-sdk/sdk/2.2.0/src/common/pico_base_headers/include/pico.h",
+                "${workspaceFolder}/build/generated/pico_base/pico/config_autogen.h"
+            ],
+            "defines": [],
+            "compilerPath": "${userHome}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json",
+            "cStandard": "c17",
+            "cppStandard": "c++14",
+            "intelliSenseMode": "linux-gcc-arm"
+        }
+    ],
+    "version": 4
+}