Added cbm 1 2

.gitignore

@@ -52,3 +52,6 @@ modules.order
 Module.symvers
 Mkfile.old
 dkms.conf
+
+# Build output
+build/

drivers/0x01_uart_cbm/.gitattributes

@@ -0,0 +1,11 @@
+# C files
+*.c linguist-language=C
+
+# Exclude from language statistics
+*.ld linguist-vendored
+*.bat linguist-vendored
+*.py linguist-vendored
+linker.ld linguist-vendored
+build.bat linguist-vendored
+clean.bat linguist-vendored
+uf2conv.py linguist-vendored

drivers/0x01_uart_cbm/.gitignore

@@ -0,0 +1,10 @@
+# Build artifacts
+*.o
+*.elf
+*.bin
+*.uf2
+compile_commands.json
+
+# OS files
+.DS_Store
+Thumbs.db

drivers/0x01_uart_cbm/.vscode/c_cpp_properties.json

@@ -0,0 +1,25 @@
+{
+    "configurations": [
+        {
+            "name": "ARM GCC",
+            "includePath": [
+                "${workspaceFolder}/**"
+            ],
+            "defines": [
+                "__GNUC__",
+                "__ARM_ARCH_8M_MAIN__",
+                "__ARMCC_VERSION"
+            ],
+            "compilerPath": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/compile_commands.json",
+            "cStandard": "c11",
+            "cppStandard": "c++17",
+            "intelliSenseMode": "gcc-arm",
+            "compilerArgs": [
+                "-mcpu=cortex-m33",
+                "-mthumb"
+            ]
+        }
+    ],
+    "version": 4
+}

drivers/0x01_uart_cbm/.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"
+    ]
+}

drivers/0x01_uart_cbm/.vscode/launch.json

@@ -0,0 +1,37 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Debug RP2350 (OpenOCD)",
+            "cwd": "${workspaceFolder}",
+            "executable": "${workspaceFolder}/uart.elf",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "searchDir": ["${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/scripts"],
+            "gdbPath": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gdb.exe",
+            "device": "RP2350",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/rp2350.cfg"
+            ],
+            "svdFile": "${env:USERPROFILE}/.pico-sdk/sdk/2.2.0/src/rp2350/hardware_regs/RP2350.svd",
+            "overrideLaunchCommands": [
+                "set arch armv8-m.main",
+                "set output-radix 16",
+                "monitor reset init",
+                "load",
+                "monitor reset halt"
+            ],
+            "openOCDPreConfigLaunchCommands": [
+                "set USE_CORE { cm0 cm1 }"
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ],
+            "preLaunchTask": "Compile Project",
+            "showDevDebugOutput": "raw"
+        }
+    ]
+}

drivers/0x01_uart_cbm/.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;${env:USERPROFILE}/.pico-sdk/picotool/2.2.0-a4/picotool;${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-a4/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:${env:HOME}/.pico-sdk/picotool/2.2.0-a4/picotool:${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"
+}

drivers/0x01_uart_cbm/.vscode/tasks.json

@@ -0,0 +1,107 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "shell",
+            "command": ".\\build.bat",
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            },
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc"
+        },
+        {
+            "label": "Clean Project",
+            "type": "shell",
+            "command": ".\\clean.bat",
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": []
+        },
+        {
+            "label": "Run Project",
+            "type": "shell",
+            "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.2.0-a4/picotool/picotool.exe",
+            "args": [
+                "load",
+                "uart.uf2",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "dependsOn": ["Compile Project"]
+        },
+        {
+            "label": "Flash",
+            "type": "shell",
+            "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; program uart.elf verify reset exit"
+            ],
+            "problemMatcher": [],
+            "dependsOn": ["Compile Project"]
+        },
+        {
+            "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"
+            }
+        }
+    ]
+}

drivers/0x01_uart_cbm/build.bat

@@ -0,0 +1,97 @@
+@echo off
+REM ==============================================================================
+REM FILE: build.bat
+REM
+REM DESCRIPTION:
+REM Build script for RP2350 bare-metal C UART driver.
+REM
+REM BRIEF:
+REM Automates the process of compiling, linking, and generating UF2 firmware.
+REM
+REM AUTHOR: Kevin Thomas
+REM CREATION DATE: 2025
+REM UPDATE DATE: 2025
+REM ==============================================================================
+
+echo Building C bare-metal version...
+
+REM ==============================================================================
+REM Compile C Source Files
+REM ==============================================================================
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c vector_table.c -o vector_table.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c reset_handler.c -o reset_handler.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c stack.c -o stack.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c xosc.c -o xosc.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c reset.c -o reset.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c coprocessor.c -o coprocessor.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c uart.c -o uart.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c delay.c -o delay.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c main.c -o main.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c image_def.c -o image_def.o
+if errorlevel 1 goto error
+
+REM ==============================================================================
+REM Link Object Files
+REM ==============================================================================
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -T linker.ld -nostdlib -Wl,--gc-sections vector_table.o reset_handler.o stack.o xosc.o reset.o coprocessor.o uart.o delay.o main.o image_def.o -o uart.elf
+if errorlevel 1 goto error
+
+REM ==============================================================================
+REM Create Raw Binary from ELF
+REM ==============================================================================
+arm-none-eabi-objcopy -O binary uart.elf uart.bin
+if errorlevel 1 goto error
+
+REM ==============================================================================
+REM Create UF2 Image for RP2350
+REM -b 0x10000000 : base address
+REM -f 0xe48bff59 : RP2350 family ID
+REM ==============================================================================
+python uf2conv.py -b 0x10000000 -f 0xe48bff59 -o uart.uf2 uart.bin
+if errorlevel 1 goto error
+
+REM ==============================================================================
+REM Success Message and Flashing Instructions
+REM ==============================================================================
+echo.
+echo =================================
+echo SUCCESS! Created uart.uf2
+echo =================================
+echo.
+echo To flash via UF2:
+echo   1. Hold BOOTSEL button
+echo   2. Plug in USB
+echo   3. Copy uart.uf2 to RP2350 drive
+echo.
+echo To flash via OpenOCD (debug probe):
+echo   openocd -f interface/cmsis-dap.cfg -f target/rp2350.cfg -c "adapter speed 5000" -c "program uart.elf verify reset exit"
+echo.
+goto end
+
+REM ==============================================================================
+REM Error Handling
+REM ==============================================================================
+:error
+echo.
+echo BUILD FAILED!
+echo.
+
+:end

drivers/0x01_uart_cbm/clean.bat

@@ -0,0 +1,30 @@
+@echo off
+REM ==============================================================================
+REM FILE: clean.bat
+REM
+REM DESCRIPTION:
+REM Clean script for RP2350 bare-metal C UART driver.
+REM
+REM BRIEF:
+REM Removes all build artifacts and generated files.
+REM
+REM AUTHOR: Kevin Thomas
+REM CREATION DATE: 2025
+REM UPDATE DATE: 2025
+REM ==============================================================================
+
+echo Cleaning build artifacts...
+
+REM Remove object files
+if exist *.o del /Q *.o
+
+REM Remove ELF file
+if exist uart.elf del /Q uart.elf
+
+REM Remove binary file
+if exist uart.bin del /Q uart.bin
+
+REM Remove UF2 file
+if exist uart.uf2 del /Q uart.uf2
+
+echo Clean complete!

drivers/0x01_uart_cbm/constants.h

@@ -0,0 +1,195 @@
+/**
+ * @file constants.h
+ * @brief Memory-mapped register structures and peripheral base addresses
+ * @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.
+ */
+
+#ifndef CONSTANTS_H
+#define CONSTANTS_H
+
+#include <stdint.h>
+
+/**
+ * Stack addresses.
+ */
+#define STACK_TOP   0x20082000U
+#define STACK_LIMIT 0x2007A000U
+
+/**
+ * XOSC (External Crystal Oscillator) Register Structure.
+ */
+typedef struct {
+    volatile uint32_t CTRL;        /**< 0x00: Control register */
+    volatile uint32_t STATUS;      /**< 0x04: Status register */
+    volatile uint32_t DORMANT;     /**< 0x08: Dormant mode */
+    volatile uint32_t STARTUP;     /**< 0x0C: Startup delay */
+    volatile uint32_t RESERVED[3]; /**< 0x10-0x18: Reserved */
+    volatile uint32_t COUNT;       /**< 0x1C: Frequency count */
+} xosc_hw_t;
+
+/**
+ * XOSC base address and pointer.
+ */
+#define XOSC_BASE 0x40048000U
+#define XOSC      ((xosc_hw_t *)XOSC_BASE)
+
+/**
+ * XOSC status bit definitions.
+ */
+#define XOSC_STATUS_STABLE_SHIFT 31U
+
+/**
+ * CPACR (Coprocessor Access Control Register) in PPB.
+ */
+#define PPB_BASE 0xE0000000U
+#define CPACR    ((volatile uint32_t *)(PPB_BASE + 0x0ED88U))
+
+/**
+ * Coprocessor access control bit definitions.
+ */
+#define CPACR_CP0_SHIFT 0U
+#define CPACR_CP1_SHIFT 1U
+
+/**
+ * CLOCKS Register Structure.
+ */
+typedef struct {
+    volatile uint32_t RESERVED0[18]; /**< 0x00-0x44: Other clock registers */
+    volatile uint32_t CLK_PERI_CTRL; /**< 0x48: Peripheral clock control */
+} clocks_hw_t;
+
+/**
+ * CLOCKS base address and pointer.
+ */
+#define CLOCKS_BASE 0x40010000U
+#define CLOCKS      ((clocks_hw_t *)CLOCKS_BASE)
+
+/**
+ * Clock control bit definitions.
+ */
+#define CLOCKS_CLK_PERI_CTRL_ENABLE_SHIFT 11U
+#define CLOCKS_CLK_PERI_CTRL_AUXSRC_SHIFT 5U
+#define CLOCKS_CLK_PERI_CTRL_AUXSRC_XOSC  4U
+
+/**
+ * RESETS Register Structure.
+ */
+typedef struct {
+    volatile uint32_t RESET;      /**< 0x00: Reset control */
+    volatile uint32_t WDSEL;      /**< 0x04: Watchdog select */
+    volatile uint32_t RESET_DONE; /**< 0x08: Reset done status */
+} resets_hw_t;
+
+/**
+ * RESETS base address and pointer.
+ */
+#define RESETS_BASE       0x40020000U
+#define RESETS             ((resets_hw_t *)RESETS_BASE)
+#define RESETS_RESET_CLEAR ((volatile uint32_t *)(RESETS_BASE + 0x3000U))
+
+/**
+ * Reset control bit definitions.
+ */
+#define RESETS_RESET_IO_BANK0_SHIFT 6U
+#define RESETS_RESET_UART0_SHIFT    26U
+
+/**
+ * IO_BANK0 GPIO Control Register (one per GPIO).
+ */
+typedef struct {
+    volatile uint32_t STATUS; /**< 0x00: GPIO status */
+    volatile uint32_t CTRL;   /**< 0x04: GPIO control */
+} io_bank0_gpio_ctrl_t;
+
+/**
+ * IO_BANK0 Register Structure.
+ */
+typedef struct {
+    io_bank0_gpio_ctrl_t GPIO[30]; /**< 0x000-0x0E8: GPIO 0-29 */
+} io_bank0_hw_t;
+
+/**
+ * IO_BANK0 base address and pointer.
+ */
+#define IO_BANK0_BASE 0x40028000U
+#define IO_BANK0      ((io_bank0_hw_t *)IO_BANK0_BASE)
+
+/**
+ * GPIO control bit definitions.
+ */
+#define IO_BANK0_CTRL_FUNCSEL_MASK  0x1FU
+#define IO_BANK0_CTRL_FUNCSEL_UART  0x02U
+#define IO_BANK0_CTRL_FUNCSEL_SIO   0x05U
+
+/**
+ * PADS_BANK0 Register Structure.
+ */
+typedef struct {
+    volatile uint32_t VOLTAGE_SELECT; /**< 0x00: Voltage select */
+    volatile uint32_t GPIO[30];       /**< 0x04-0x78: GPIO 0-29 pad control */
+} pads_bank0_hw_t;
+
+/**
+ * PADS_BANK0 base address and pointer.
+ */
+#define PADS_BANK0_BASE 0x40038000U
+#define PADS_BANK0      ((pads_bank0_hw_t *)PADS_BANK0_BASE)
+
+/**
+ * Pad control bit definitions.
+ */
+#define PADS_BANK0_OD_SHIFT  7U
+#define PADS_BANK0_IE_SHIFT  6U
+#define PADS_BANK0_ISO_SHIFT 8U
+
+/**
+ * UART0 base address.
+ */
+#define UART0_BASE 0x40070000U
+
+/**
+ * UART register offsets (as word indices from UART0_BASE).
+ */
+#define UART_DR_OFFSET      (0x00U / 4U)
+#define UART_FR_OFFSET      (0x18U / 4U)
+#define UART_IBRD_OFFSET    (0x24U / 4U)
+#define UART_FBRD_OFFSET    (0x28U / 4U)
+#define UART_LCR_H_OFFSET  (0x2CU / 4U)
+#define UART_CR_OFFSET      (0x30U / 4U)
+
+/**
+ * UART flag register bit definitions.
+ */
+#define UART_FR_TXFF_MASK 32U
+#define UART_FR_RXFE_MASK 16U
+
+/**
+ * UART line control and enable values.
+ */
+#define UART_LCR_H_8N1_FIFO 0x70U
+#define UART_CR_ENABLE       ((3U << 8) | 1U)
+
+#endif // CONSTANTS_H

drivers/0x01_uart_cbm/coprocessor.c

@@ -0,0 +1,48 @@
+/**
+ * @file coprocessor.c
+ * @brief Coprocessor access control enable 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.
+ */
+
+#include "coprocessor.h"
+#include "constants.h"
+
+void Enable_Coprocessor(void) {
+    uint32_t value;
+
+    // read CPACR value
+    value = *CPACR;
+    // set CP1: Ctrl access priv coproc 1 bit
+    value |= (1U << CPACR_CP1_SHIFT);
+    // set CP0: Ctrl access priv coproc 0 bit
+    value |= (1U << CPACR_CP0_SHIFT);
+    // store value into CPACR
+    *CPACR = value;
+    // data sync barrier
+    __asm__ volatile ("dsb");
+    // instruction sync barrier
+    __asm__ volatile ("isb");
+}

drivers/0x01_uart_cbm/coprocessor.h

@@ -0,0 +1,45 @@
+/**
+ * @file coprocessor.h
+ * @brief Coprocessor access control enable 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.
+ */
+
+#ifndef COPROCESSOR_H
+#define COPROCESSOR_H
+
+/**
+ * @brief Enable coprocessor access via CPACR
+ *
+ * Grants full access to coprocessors 0 and 1 by setting the
+ * corresponding bits in the Coprocessor Access Control Register,
+ * then issues DSB and ISB barriers.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Enable_Coprocessor(void);
+
+#endif // COPROCESSOR_H

drivers/0x01_uart_cbm/delay.c

@@ -0,0 +1,46 @@
+/**
+ * @file delay.c
+ * @brief Millisecond delay functions based on a 14.5 MHz clock
+ * @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.
+ */
+
+#include "delay.h"
+
+void Delay_MS(uint32_t ms) {
+    if (ms == 0) {
+        return;
+    }
+    __asm__ volatile (
+        "mov r4, #3600\n\t"
+        "mul r5, %0, r4\n\t"
+        "1:\n\t"
+        "subs r5, #1\n\t"
+        "bne 1b\n\t"
+        :
+        : "r" (ms)
+        : "r4", "r5", "cc"
+    );
+}

drivers/0x01_uart_cbm/delay.h

@@ -0,0 +1,45 @@
+/**
+ * @file delay.h
+ * @brief Millisecond delay functions based on a 14.5 MHz clock
+ * @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.
+ */
+
+#ifndef DELAY_H
+#define DELAY_H
+
+#include <stdint.h>
+
+/**
+ * @brief Delay for the specified number of milliseconds
+ *
+ * Busy-waits using a calibrated loop count (3600 iterations per ms)
+ * based on a 14.5 MHz clock. Returns immediately if ms is zero.
+ *
+ * @param ms Number of milliseconds to delay
+ */
+void Delay_MS(uint32_t ms);
+
+#endif // DELAY_H

drivers/0x01_uart_cbm/image_def.c

@@ -0,0 +1,48 @@
+/**
+ * @file image_def.c
+ * @brief RP2350 IMAGE_DEF block for boot ROM image recognition
+ * @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.
+ */
+
+#include <stdint.h>
+
+/**
+ * IMAGE_DEF block structure placed in flash.
+ * Must appear within the first 4 KB for the boot ROM to accept the image.
+ */
+__attribute__((section(".embedded_block"), used))
+const uint8_t picobin_block[] = {
+    // PICOBIN_BLOCK_MARKER_START (word: 0xffffded3)
+    0xD3, 0xDE, 0xFF, 0xFF,
+    // PICOBIN_BLOCK_ITEM_1BS_IMAGE_TYPE
+    0x42, 0x01, 0x21, 0x10,
+    // PICOBIN_BLOCK_ITEM_2BS_LAST
+    0xFF, 0x01, 0x00, 0x00,
+    // Relative pointer to next block (loop to self)
+    0x00, 0x00, 0x00, 0x00,
+    // PICOBIN_BLOCK_MARKER_END (word: 0xab123579)
+    0x79, 0x35, 0x12, 0xAB
+};

drivers/0x01_uart_cbm/linker.ld

@@ -0,0 +1,106 @@
+/**
+ * @file linker.ld
+ * @brief Minimal linker script for bare-metal RP2350 development
+ * @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.
+ */
+
+ENTRY(Reset_Handler)
+
+/**
+ * Define memory regions.
+ */
+__XIP_BASE   = 0x10000000;
+__XIP_SIZE   = 32M;
+
+__SRAM_BASE  = 0x20000000;
+__SRAM_SIZE  = 512K;
+__STACK_SIZE = 32K;
+
+MEMORY
+{
+  RAM   (rwx) : ORIGIN = __SRAM_BASE, LENGTH = __SRAM_SIZE
+  FLASH (rx)  : ORIGIN = __XIP_BASE,  LENGTH = __XIP_SIZE
+}
+
+/**
+ * Program headers.
+ */
+PHDRS
+{
+  text PT_LOAD FLAGS(5);
+}
+
+/**
+ * Section placement.
+ */
+SECTIONS
+{
+  . = ORIGIN(FLASH);
+
+  /**
+   * Vector table MUST be first at 0x10000000.
+   */
+  .vectors :
+  {
+    KEEP(*(.vectors))
+  } > FLASH :text
+
+  ASSERT((ADDR(.vectors) == ORIGIN(FLASH)),
+         "Vector table must be at start of flash (0x10000000)")
+
+  /**
+   * Text and read-only data.
+   */
+  .text :
+  {
+    . = ALIGN(4);
+    *(.text*)
+    *(.rodata*)
+    KEEP(*(.init))
+    KEEP(*(.fini))
+    KEEP(*(.ARM.attributes))
+  } > FLASH :text
+
+  /**
+   * IMAGE_DEF block at end of code.
+   */
+  .embedded_block :
+  {
+    KEEP(*(.embedded_block))
+  } > FLASH :text
+
+  /**
+   * Non-secure stack symbols.
+   */
+  __StackTop   = ORIGIN(RAM) + LENGTH(RAM);
+  __StackLimit = __StackTop - __STACK_SIZE;
+  __stack      = __StackTop;
+  _stack_top   = __StackTop;
+
+  .stack (NOLOAD) : { . = ALIGN(8); } > RAM
+
+  PROVIDE(__Vectors = ADDR(.vectors));
+}

drivers/0x01_uart_cbm/main.c

@@ -0,0 +1,78 @@
+/**
+ * @file main.c
+ * @brief UART demonstration: echo received characters back in uppercase
+ * @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 bare-metal UART0 using the uart driver (uart.h / uart.c).
+ * Characters typed into a terminal via a USB-to-UART adapter are echoed
+ * back in uppercase, illustrating full-duplex raw UART operation at the
+ * register level without the Pico SDK.
+ *
+ * Wiring:
+ *   GPIO0 (TX) -> USB-to-UART adapter RX
+ *   GPIO1 (RX) -> USB-to-UART adapter TX
+ *   GND        -> USB-to-UART adapter GND
+ */
+
+#include "uart.h"
+
+/**
+ * @brief Echo received characters back as uppercase
+ *
+ * @details Polls UART0 for incoming data. When a character is
+ *          available, reads it, converts to uppercase, and echoes
+ *          it back. Never returns.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _echo_uppercase(void) {
+    while (1) {
+        if (uart_driver_is_readable()) {
+            char c     = uart_driver_getchar();
+            char upper = uart_driver_to_upper(c);
+            uart_driver_putchar(upper);
+        }
+    }
+}
+
+/**
+ * @brief Application entry point for the UART uppercase echo demo
+ *
+ * Prints two banner messages over UART0, then enters the echo loop.
+ * UART0 hardware initialization is performed by Reset_Handler before
+ * main() is called.
+ *
+ * @return int Does not return
+ */
+int main(void) {
+    uart_driver_puts("UART driver ready (115200 8N1)\r\n");
+    uart_driver_puts("Type characters to echo them back in UPPERCASE:\r\n");
+    _echo_uppercase();
+    return 0;
+}

drivers/0x01_uart_cbm/reset.c

@@ -0,0 +1,45 @@
+/**
+ * @file reset.c
+ * @brief Reset controller functions for subsystem initialization
+ * @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.
+ */
+
+#include "reset.h"
+#include "constants.h"
+
+void Init_Subsystem(void) {
+    uint32_t value;
+
+    // read RESETS->RESET value
+    value = RESETS->RESET;
+    // clear IO_BANK0 bit
+    value &= ~(1U << RESETS_RESET_IO_BANK0_SHIFT);
+    // store value into RESETS->RESET address
+    RESETS->RESET = value;
+    // wait until done
+    while ((RESETS->RESET_DONE & (1U << RESETS_RESET_IO_BANK0_SHIFT)) == 0) {
+    }
+}

drivers/0x01_uart_cbm/reset.h

@@ -0,0 +1,44 @@
+/**
+ * @file reset.h
+ * @brief Reset controller functions for subsystem initialization
+ * @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.
+ */
+
+#ifndef RESET_H
+#define RESET_H
+
+/**
+ * @brief Initialize the IO_BANK0 subsystem by clearing its reset bit
+ *
+ * Clears the IO_BANK0 reset bit in the Reset controller and waits
+ * until the RESET_DONE register confirms the block is out of reset.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Init_Subsystem(void);
+
+#endif // RESET_H

drivers/0x01_uart_cbm/reset_handler.c

@@ -0,0 +1,50 @@
+/**
+ * @file reset_handler.c
+ * @brief Reset handler entry point after power-on or system reset
+ * @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.
+ */
+
+#include "reset_handler.h"
+#include "stack.h"
+#include "xosc.h"
+#include "reset.h"
+#include "uart.h"
+#include "coprocessor.h"
+
+extern int main(void);
+
+void __attribute__((naked, noreturn)) Reset_Handler(void) {
+    __asm__ volatile (
+        "bl Init_Stack\n\t"
+        "bl Init_XOSC\n\t"
+        "bl Enable_XOSC_Peri_Clock\n\t"
+        "bl Init_Subsystem\n\t"
+        "bl UART_Release_Reset\n\t"
+        "bl UART_Init\n\t"
+        "bl Enable_Coprocessor\n\t"
+        "b main\n\t"
+    );
+}

drivers/0x01_uart_cbm/reset_handler.h

@@ -0,0 +1,45 @@
+/**
+ * @file reset_handler.h
+ * @brief Reset handler entry point after power-on or system reset
+ * @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.
+ */
+
+#ifndef RESET_HANDLER_H
+#define RESET_HANDLER_H
+
+/**
+ * @brief Reset handler for the RP2350
+ *
+ * Entry point after reset. Performs stack initialization, XOSC setup,
+ * subsystem reset release, UART initialization, coprocessor enable,
+ * and branches to main().
+ *
+ * @param   None
+ * @retval  None
+ */
+void Reset_Handler(void) __attribute__((noreturn));
+
+#endif // RESET_HANDLER_H

drivers/0x01_uart_cbm/stack.c

@@ -0,0 +1,46 @@
+/**
+ * @file stack.c
+ * @brief Stack pointer initialization for MSP/PSP and their limits
+ * @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.
+ */
+
+#include "stack.h"
+#include "constants.h"
+
+void Init_Stack(void) {
+    __asm__ volatile (
+        "ldr   r0, =%0\n\t"
+        "msr   PSP, r0\n\t"
+        "ldr   r0, =%1\n\t"
+        "msr   MSPLIM, r0\n\t"
+        "msr   PSPLIM, r0\n\t"
+        "ldr   r0, =%0\n\t"
+        "msr   MSP, r0\n\t"
+        :
+        : "i" (STACK_TOP), "i" (STACK_LIMIT)
+        : "r0"
+    );
+}

drivers/0x01_uart_cbm/stack.h

@@ -0,0 +1,44 @@
+/**
+ * @file stack.h
+ * @brief Stack pointer initialization for MSP/PSP and their limits
+ * @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.
+ */
+
+#ifndef STACK_H
+#define STACK_H
+
+/**
+ * @brief Initialize stack pointers
+ *
+ * Sets Main and Process Stack Pointers (MSP/PSP) and their limits
+ * using the STACK_TOP and STACK_LIMIT values from constants.h.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Init_Stack(void);
+
+#endif // STACK_H

drivers/0x01_uart_cbm/uart.c

@@ -0,0 +1,165 @@
+/**
+ * @file uart.c
+ * @brief Implementation of the bare-metal UART0 driver
+ * @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.
+ */
+
+#include "uart.h"
+#include "constants.h"
+
+#define UART_BASE ((volatile uint32_t *)UART0_BASE)
+
+/**
+ * @brief Clear the UART0 reset bit in the reset controller
+ *
+ * @details Reads RESETS->RESET, clears bit 26 (UART0), and writes
+ *          the value back.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_clear_reset_bit(void) {
+    uint32_t value;
+
+    // read RESETS->RESET value
+    value = RESETS->RESET;
+    // clear UART0 reset bit (bit 26)
+    value &= ~(1U << RESETS_RESET_UART0_SHIFT);
+    // write value back to RESETS->RESET
+    RESETS->RESET = value;
+}
+
+/**
+ * @brief Wait until the UART0 block is out of reset
+ *
+ * @details Polls RESETS->RESET_DONE until bit 26 (UART0) is set.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_wait_reset_done(void) {
+    // loop until UART0 is out of reset
+    while ((RESETS->RESET_DONE & (1U << RESETS_RESET_UART0_SHIFT)) == 0) {
+    }
+}
+
+/**
+ * @brief Configure GPIO pins 0 (TX) and 1 (RX) for UART function
+ *
+ * @details Sets IO_BANK0 FUNCSEL to UART (0x02) for both pins and
+ *          programs the corresponding pad controls.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_configure_pins(void) {
+    // FUNCSEL = 2 -> select UART function
+    IO_BANK0->GPIO[0].CTRL = IO_BANK0_CTRL_FUNCSEL_UART;
+    IO_BANK0->GPIO[1].CTRL = IO_BANK0_CTRL_FUNCSEL_UART;
+    // pad config value for TX (pull/func recommended)
+    PADS_BANK0->GPIO[0] = 0x04;
+    // pad config value for RX (input enable)
+    PADS_BANK0->GPIO[1] = 0x40;
+}
+
+/**
+ * @brief Set UART0 baud rate divisors for 115200 baud at 14.5 MHz
+ *
+ * @details Programs UARTIBRD = 6 and UARTFBRD = 33 for the integer
+ *          and fractional baud rate divisors respectively.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_set_baud(void) {
+    // disable UART while configuring
+    UART_BASE[UART_CR_OFFSET] = 0;
+    // set integer baud divisor
+    UART_BASE[UART_IBRD_OFFSET] = 6;
+    // set fractional baud divisor
+    UART_BASE[UART_FBRD_OFFSET] = 33;
+}
+
+/**
+ * @brief Configure line control and enable UART0
+ *
+ * @details Sets 8-bit word length with FIFOs enabled, then enables
+ *          UART0 with both TX and RX.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_enable(void) {
+    // configure line control: FIFO enable + 8-bit
+    UART_BASE[UART_LCR_H_OFFSET] = UART_LCR_H_8N1_FIFO;
+    // enable UART with TX and RX enabled
+    UART_BASE[UART_CR_OFFSET] = UART_CR_ENABLE;
+}
+
+void UART_Release_Reset(void) {
+    _uart_clear_reset_bit();
+    _uart_wait_reset_done();
+}
+
+void UART_Init(void) {
+    _uart_configure_pins();
+    _uart_set_baud();
+    _uart_enable();
+}
+
+bool uart_driver_is_readable(void) {
+    // test bit 4, RX FIFO empty (RXFE)
+    return (UART_BASE[UART_FR_OFFSET] & UART_FR_RXFE_MASK) == 0;
+}
+
+char uart_driver_getchar(void) {
+    // wait for RX FIFO to be not empty
+    while (UART_BASE[UART_FR_OFFSET] & UART_FR_RXFE_MASK) {
+    }
+    // read data from UARTDR
+    return (char)(UART_BASE[UART_DR_OFFSET] & 0xFF);
+}
+
+void uart_driver_putchar(char c) {
+    // wait for TX FIFO to be not full
+    while (UART_BASE[UART_FR_OFFSET] & UART_FR_TXFF_MASK) {
+    }
+    // write data to UARTDR
+    UART_BASE[UART_DR_OFFSET] = (uint32_t)c;
+}
+
+void uart_driver_puts(const char *str) {
+    while (*str) {
+        uart_driver_putchar(*str++);
+    }
+}
+
+char uart_driver_to_upper(char c) {
+    if (c >= 'a' && c <= 'z') {
+        return (char)(c - 32);
+    }
+    return c;
+}

drivers/0x01_uart_cbm/uart.h

@@ -0,0 +1,111 @@
+/**
+ * @file uart.h
+ * @brief Header for bare-metal UART0 driver (raw TX/RX, GPIO 0/1)
+ * @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.
+ */
+
+#ifndef UART_H
+#define UART_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/**
+ * @brief Release UART0 from reset and wait until it is ready
+ *
+ * Clears the UART0 reset bit in the Reset controller and polls
+ * RESET_DONE until the UART0 block is out of reset.
+ *
+ * @param   None
+ * @retval  None
+ */
+void UART_Release_Reset(void);
+
+/**
+ * @brief Initialize UART0 (pins, baud divisors, line control, enable)
+ *
+ * Configures IO_BANK0 pins 0 (TX) and 1 (RX) to the UART function,
+ * programs pad controls, sets baud rate divisors (IBRD=6, FBRD=33
+ * for 115200 baud at 14.5 MHz), configures 8N1 with FIFOs, and
+ * enables UART0 with TX and RX.
+ *
+ * @param   None
+ * @retval  None
+ */
+void UART_Init(void);
+
+/**
+ * @brief Check whether a received character is waiting in the UART FIFO
+ *
+ * Returns immediately without blocking. Use this to poll for incoming
+ * data before calling uart_driver_getchar().
+ *
+ * @return bool true if at least one byte is available, false otherwise
+ */
+bool uart_driver_is_readable(void);
+
+/**
+ * @brief Read one character from UART0 (blocking)
+ *
+ * Blocks until a byte arrives in the receive FIFO, then returns it.
+ * Prefer pairing with uart_driver_is_readable() to avoid indefinite blocking.
+ *
+ * @return char The received character
+ */
+char uart_driver_getchar(void);
+
+/**
+ * @brief Transmit one character over UART0 (blocking)
+ *
+ * Waits until the transmit FIFO has space, then writes the character
+ * to UARTDR.
+ *
+ * @param c Character to transmit
+ */
+void uart_driver_putchar(char c);
+
+/**
+ * @brief Transmit a null-terminated string over UART0
+ *
+ * Calls uart_driver_putchar() for every character in the string up to
+ * and not including the null terminator.
+ *
+ * @param str Pointer to the null-terminated ASCII string to send
+ */
+void uart_driver_puts(const char *str);
+
+/**
+ * @brief Convert a lowercase ASCII character to uppercase
+ *
+ * Returns the uppercase equivalent if the character is in 'a'-'z';
+ * all other characters are passed through unchanged.
+ *
+ * @param c Input character
+ * @return char Uppercase equivalent, or the original character
+ */
+char uart_driver_to_upper(char c);
+
+#endif // UART_H

drivers/0x01_uart_cbm/uf2conv.py

@@ -0,0 +1,365 @@
+#!/usr/bin/env python3
+import sys
+import struct
+import subprocess
+import re
+import os
+import os.path
+import argparse
+import json
+from time import sleep
+
+
+UF2_MAGIC_START0 = 0x0A324655 # "UF2\n"
+UF2_MAGIC_START1 = 0x9E5D5157 # Randomly selected
+UF2_MAGIC_END    = 0x0AB16F30 # Ditto
+
+INFO_FILE = "/INFO_UF2.TXT"
+
+appstartaddr = 0x2000
+familyid = 0x0
+
+
+def is_uf2(buf):
+    w = struct.unpack("<II", buf[0:8])
+    return w[0] == UF2_MAGIC_START0 and w[1] == UF2_MAGIC_START1
+
+def is_hex(buf):
+    try:
+        w = buf[0:30].decode("utf-8")
+    except UnicodeDecodeError:
+        return False
+    if w[0] == ':' and re.match(rb"^[:0-9a-fA-F\r\n]+$", buf):
+        return True
+    return False
+
+def convert_from_uf2(buf):
+    global appstartaddr
+    global familyid
+    numblocks = len(buf) // 512
+    curraddr = None
+    currfamilyid = None
+    families_found = {}
+    prev_flag = None
+    all_flags_same = True
+    outp = []
+    for blockno in range(numblocks):
+        ptr = blockno * 512
+        block = buf[ptr:ptr + 512]
+        hd = struct.unpack(b"<IIIIIIII", block[0:32])
+        if hd[0] != UF2_MAGIC_START0 or hd[1] != UF2_MAGIC_START1:
+            print("Skipping block at " + ptr + "; bad magic")
+            continue
+        if hd[2] & 1:
+            # NO-flash flag set; skip block
+            continue
+        datalen = hd[4]
+        if datalen > 476:
+            assert False, "Invalid UF2 data size at " + ptr
+        newaddr = hd[3]
+        if (hd[2] & 0x2000) and (currfamilyid == None):
+            currfamilyid = hd[7]
+        if curraddr == None or ((hd[2] & 0x2000) and hd[7] != currfamilyid):
+            currfamilyid = hd[7]
+            curraddr = newaddr
+            if familyid == 0x0 or familyid == hd[7]:
+                appstartaddr = newaddr
+        padding = newaddr - curraddr
+        if padding < 0:
+            assert False, "Block out of order at " + ptr
+        if padding > 10*1024*1024:
+            assert False, "More than 10M of padding needed at " + ptr
+        if padding % 4 != 0:
+            assert False, "Non-word padding size at " + ptr
+        while padding > 0:
+            padding -= 4
+            outp.append(b"\x00\x00\x00\x00")
+        if familyid == 0x0 or ((hd[2] & 0x2000) and familyid == hd[7]):
+            outp.append(block[32 : 32 + datalen])
+        curraddr = newaddr + datalen
+        if hd[2] & 0x2000:
+            if hd[7] in families_found.keys():
+                if families_found[hd[7]] > newaddr:
+                    families_found[hd[7]] = newaddr
+            else:
+                families_found[hd[7]] = newaddr
+        if prev_flag == None:
+            prev_flag = hd[2]
+        if prev_flag != hd[2]:
+            all_flags_same = False
+        if blockno == (numblocks - 1):
+            print("--- UF2 File Header Info ---")
+            families = load_families()
+            for family_hex in families_found.keys():
+                family_short_name = ""
+                for name, value in families.items():
+                    if value == family_hex:
+                        family_short_name = name
+                print("Family ID is {:s}, hex value is 0x{:08x}".format(family_short_name,family_hex))
+                print("Target Address is 0x{:08x}".format(families_found[family_hex]))
+            if all_flags_same:
+                print("All block flag values consistent, 0x{:04x}".format(hd[2]))
+            else:
+                print("Flags were not all the same")
+            print("----------------------------")
+            if len(families_found) > 1 and familyid == 0x0:
+                outp = []
+                appstartaddr = 0x0
+    return b"".join(outp)
+
+def convert_to_carray(file_content):
+    outp = "const unsigned long bindata_len = %d;\n" % len(file_content)
+    outp += "const unsigned char bindata[] __attribute__((aligned(16))) = {"
+    for i in range(len(file_content)):
+        if i % 16 == 0:
+            outp += "\n"
+        outp += "0x%02x, " % file_content[i]
+    outp += "\n};\n"
+    return bytes(outp, "utf-8")
+
+def convert_to_uf2(file_content):
+    global familyid
+    datapadding = b""
+    while len(datapadding) < 512 - 256 - 32 - 4:
+        datapadding += b"\x00\x00\x00\x00"
+    numblocks = (len(file_content) + 255) // 256
+    outp = []
+    for blockno in range(numblocks):
+        ptr = 256 * blockno
+        chunk = file_content[ptr:ptr + 256]
+        flags = 0x0
+        if familyid:
+            flags |= 0x2000
+        hd = struct.pack(b"<IIIIIIII",
+            UF2_MAGIC_START0, UF2_MAGIC_START1,
+            flags, ptr + appstartaddr, 256, blockno, numblocks, familyid)
+        while len(chunk) < 256:
+            chunk += b"\x00"
+        block = hd + chunk + datapadding + struct.pack(b"<I", UF2_MAGIC_END)
+        assert len(block) == 512
+        outp.append(block)
+    return b"".join(outp)
+
+class Block:
+    def __init__(self, addr, default_data=0xFF):
+        self.addr = addr
+        self.bytes = bytearray([default_data] * 256)
+
+    def encode(self, blockno, numblocks):
+        global familyid
+        flags = 0x0
+        if familyid:
+            flags |= 0x2000
+        hd = struct.pack("<IIIIIIII",
+            UF2_MAGIC_START0, UF2_MAGIC_START1,
+            flags, self.addr, 256, blockno, numblocks, familyid)
+        hd += self.bytes[0:256]
+        while len(hd) < 512 - 4:
+            hd += b"\x00"
+        hd += struct.pack("<I", UF2_MAGIC_END)
+        return hd
+
+def convert_from_hex_to_uf2(buf):
+    global appstartaddr
+    appstartaddr = None
+    upper = 0
+    currblock = None
+    blocks = []
+    for line in buf.split('\n'):
+        if line[0] != ":":
+            continue
+        i = 1
+        rec = []
+        while i < len(line) - 1:
+            rec.append(int(line[i:i+2], 16))
+            i += 2
+        tp = rec[3]
+        if tp == 4:
+            upper = ((rec[4] << 8) | rec[5]) << 16
+        elif tp == 2:
+            upper = ((rec[4] << 8) | rec[5]) << 4
+        elif tp == 1:
+            break
+        elif tp == 0:
+            addr = upper + ((rec[1] << 8) | rec[2])
+            if appstartaddr == None:
+                appstartaddr = addr
+            i = 4
+            while i < len(rec) - 1:
+                if not currblock or currblock.addr & ~0xff != addr & ~0xff:
+                    currblock = Block(addr & ~0xff)
+                    blocks.append(currblock)
+                currblock.bytes[addr & 0xff] = rec[i]
+                addr += 1
+                i += 1
+    numblocks = len(blocks)
+    resfile = b""
+    for i in range(0, numblocks):
+        resfile += blocks[i].encode(i, numblocks)
+    return resfile
+
+def to_str(b):
+    return b.decode("utf-8")
+
+def get_drives():
+    drives = []
+    if sys.platform == "win32":
+        r = subprocess.check_output([
+            "powershell",
+            "-Command",
+            '(Get-WmiObject Win32_LogicalDisk -Filter "VolumeName=\'RPI-RP2\'").DeviceID'
+            ])
+        drive = to_str(r).strip()
+        if drive:
+            drives.append(drive)
+    else:
+        searchpaths = ["/mnt", "/media"]
+        if sys.platform == "darwin":
+            searchpaths = ["/Volumes"]
+        elif sys.platform == "linux":
+            searchpaths += ["/media/" + os.environ["USER"], "/run/media/" + os.environ["USER"]]
+            if "SUDO_USER" in os.environ.keys():
+                searchpaths += ["/media/" + os.environ["SUDO_USER"]]
+                searchpaths += ["/run/media/" + os.environ["SUDO_USER"]]
+
+        for rootpath in searchpaths:
+            if os.path.isdir(rootpath):
+                for d in os.listdir(rootpath):
+                    if os.path.isdir(os.path.join(rootpath, d)):
+                        drives.append(os.path.join(rootpath, d))
+
+
+    def has_info(d):
+        try:
+            return os.path.isfile(d + INFO_FILE)
+        except:
+            return False
+
+    return list(filter(has_info, drives))
+
+
+def board_id(path):
+    with open(path + INFO_FILE, mode='r') as file:
+        file_content = file.read()
+    return re.search(r"Board-ID: ([^\r\n]*)", file_content).group(1)
+
+
+def list_drives():
+    for d in get_drives():
+        print(d, board_id(d))
+
+
+def write_file(name, buf):
+    with open(name, "wb") as f:
+        f.write(buf)
+    print("Wrote %d bytes to %s" % (len(buf), name))
+
+
+def load_families():
+    # The expectation is that the `uf2families.json` file is in the same
+    # directory as this script. Make a path that works using `__file__`
+    # which contains the full path to this script.
+    filename = "uf2families.json"
+    pathname = os.path.join(os.path.dirname(os.path.abspath(__file__)), filename)
+    with open(pathname) as f:
+        raw_families = json.load(f)
+
+    families = {}
+    for family in raw_families:
+        families[family["short_name"]] = int(family["id"], 0)
+
+    return families
+
+
+def main():
+    global appstartaddr, familyid
+    def error(msg):
+        print(msg, file=sys.stderr)
+        sys.exit(1)
+    parser = argparse.ArgumentParser(description='Convert to UF2 or flash directly.')
+    parser.add_argument('input', metavar='INPUT', type=str, nargs='?',
+                        help='input file (HEX, BIN or UF2)')
+    parser.add_argument('-b', '--base', dest='base', type=str,
+                        default="0x2000",
+                        help='set base address of application for BIN format (default: 0x2000)')
+    parser.add_argument('-f', '--family', dest='family', type=str,
+                        default="0x0",
+                        help='specify familyID - number or name (default: 0x0)')
+    parser.add_argument('-o', '--output', metavar="FILE", dest='output', type=str,
+                        help='write output to named file; defaults to "flash.uf2" or "flash.bin" where sensible')
+    parser.add_argument('-d', '--device', dest="device_path",
+                        help='select a device path to flash')
+    parser.add_argument('-l', '--list', action='store_true',
+                        help='list connected devices')
+    parser.add_argument('-c', '--convert', action='store_true',
+                        help='do not flash, just convert')
+    parser.add_argument('-D', '--deploy', action='store_true',
+                        help='just flash, do not convert')
+    parser.add_argument('-w', '--wait', action='store_true',
+                        help='wait for device to flash')
+    parser.add_argument('-C', '--carray', action='store_true',
+                        help='convert binary file to a C array, not UF2')
+    parser.add_argument('-i', '--info', action='store_true',
+                        help='display header information from UF2, do not convert')
+    args = parser.parse_args()
+    appstartaddr = int(args.base, 0)
+
+    families = load_families()
+
+    if args.family.upper() in families:
+        familyid = families[args.family.upper()]
+    else:
+        try:
+            familyid = int(args.family, 0)
+        except ValueError:
+            error("Family ID needs to be a number or one of: " + ", ".join(families.keys()))
+
+    if args.list:
+        list_drives()
+    else:
+        if not args.input:
+            error("Need input file")
+        with open(args.input, mode='rb') as f:
+            inpbuf = f.read()
+        from_uf2 = is_uf2(inpbuf)
+        ext = "uf2"
+        if args.deploy:
+            outbuf = inpbuf
+        elif from_uf2 and not args.info:
+            outbuf = convert_from_uf2(inpbuf)
+            ext = "bin"
+        elif from_uf2 and args.info:
+            outbuf = ""
+            convert_from_uf2(inpbuf)
+        elif is_hex(inpbuf):
+            outbuf = convert_from_hex_to_uf2(inpbuf.decode("utf-8"))
+        elif args.carray:
+            outbuf = convert_to_carray(inpbuf)
+            ext = "h"
+        else:
+            outbuf = convert_to_uf2(inpbuf)
+        if not args.deploy and not args.info:
+            print("Converted to %s, output size: %d, start address: 0x%x" %
+                  (ext, len(outbuf), appstartaddr))
+        if args.convert or ext != "uf2":
+            if args.output == None:
+                args.output = "flash." + ext
+        if args.output:
+            write_file(args.output, outbuf)
+        if ext == "uf2" and not args.convert and not args.info:
+            drives = get_drives()
+            if len(drives) == 0:
+                if args.wait:
+                    print("Waiting for drive to deploy...")
+                    while len(drives) == 0:
+                        sleep(0.1)
+                        drives = get_drives()
+                elif not args.output:
+                    error("No drive to deploy.")
+            for d in drives:
+                print("Flashing %s (%s)" % (d, board_id(d)))
+                write_file(d + "/NEW.UF2", outbuf)
+
+
+if __name__ == "__main__":
+    main()

drivers/0x01_uart_cbm/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"
+    }
+]

drivers/0x01_uart_cbm/vector_table.c

@@ -0,0 +1,46 @@
+/**
+ * @file vector_table.c
+ * @brief Vector table with initial stack pointer and reset handler
+ * @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.
+ */
+
+#include <stdint.h>
+
+extern uint32_t _stack_top;
+extern void Reset_Handler(void);
+
+typedef void (*vector_func_t)(void);
+
+/**
+ * Vector table placed in .vectors section.
+ * The Thumb bit (bit 0 = 1) is automatically set by the linker
+ * for function pointers in Thumb mode.
+ */
+__attribute__((section(".vectors"), used))
+const void *_vectors[2] = {
+    &_stack_top,
+    Reset_Handler
+};

drivers/0x01_uart_cbm/xosc.c

@@ -0,0 +1,54 @@
+/**
+ * @file xosc.c
+ * @brief External crystal oscillator (XOSC) initialization and clock enable
+ * @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.
+ */
+
+#include "xosc.h"
+#include "constants.h"
+
+void Init_XOSC(void) {
+    // set delay 50,000 cycles
+    XOSC->STARTUP = 0x00C4U;
+    // set 1_15MHz, freq range, actual 14.5MHz
+    XOSC->CTRL = 0x00FABAA0U;
+    // wait until stable bit is set
+    while ((XOSC->STATUS & (1U << XOSC_STATUS_STABLE_SHIFT)) == 0) {
+    }
+}
+
+void Enable_XOSC_Peri_Clock(void) {
+    uint32_t value;
+
+    // read CLK_PERI_CTRL value
+    value = CLOCKS->CLK_PERI_CTRL;
+    // set ENABLE bit
+    value |= (1U << CLOCKS_CLK_PERI_CTRL_ENABLE_SHIFT);
+    // set AUXSRC: XOSC_CLKSRC
+    value |= (CLOCKS_CLK_PERI_CTRL_AUXSRC_XOSC << CLOCKS_CLK_PERI_CTRL_AUXSRC_SHIFT);
+    // store value into CLK_PERI_CTRL
+    CLOCKS->CLK_PERI_CTRL = value;
+}

drivers/0x01_uart_cbm/xosc.h

@@ -0,0 +1,55 @@
+/**
+ * @file xosc.h
+ * @brief External crystal oscillator (XOSC) initialization and clock enable
+ * @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.
+ */
+
+#ifndef XOSC_H
+#define XOSC_H
+
+/**
+ * @brief Initialize the external crystal oscillator and wait until stable
+ *
+ * Configures the XOSC startup delay and frequency range, then polls
+ * the status register until the STABLE bit is set.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Init_XOSC(void);
+
+/**
+ * @brief Enable the XOSC peripheral clock
+ *
+ * Sets the peripheral clock to use XOSC as its auxiliary source and
+ * enables it via CLK_PERI_CTRL.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Enable_XOSC_Peri_Clock(void);
+
+#endif // XOSC_H

drivers/0x02_blink_cbm/.gitattributes

@@ -0,0 +1,11 @@
+# C files
+*.c linguist-language=C
+
+# Exclude from language statistics
+*.ld linguist-vendored
+*.bat linguist-vendored
+*.py linguist-vendored
+linker.ld linguist-vendored
+build.bat linguist-vendored
+clean.bat linguist-vendored
+uf2conv.py linguist-vendored

drivers/0x02_blink_cbm/.gitignore

@@ -0,0 +1,10 @@
+# Build artifacts
+*.o
+*.elf
+*.bin
+*.uf2
+compile_commands.json
+
+# OS files
+.DS_Store
+Thumbs.db

drivers/0x02_blink_cbm/.vscode/c_cpp_properties.json

@@ -0,0 +1,25 @@
+{
+    "configurations": [
+        {
+            "name": "ARM GCC",
+            "includePath": [
+                "${workspaceFolder}/**"
+            ],
+            "defines": [
+                "__GNUC__",
+                "__ARM_ARCH_8M_MAIN__",
+                "__ARMCC_VERSION"
+            ],
+            "compilerPath": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc.exe",
+            "compileCommands": "${workspaceFolder}/compile_commands.json",
+            "cStandard": "c11",
+            "cppStandard": "c++17",
+            "intelliSenseMode": "gcc-arm",
+            "compilerArgs": [
+                "-mcpu=cortex-m33",
+                "-mthumb"
+            ]
+        }
+    ],
+    "version": 4
+}

drivers/0x02_blink_cbm/.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"
+    ]
+}

drivers/0x02_blink_cbm/.vscode/launch.json

@@ -0,0 +1,37 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Debug RP2350 (OpenOCD)",
+            "cwd": "${workspaceFolder}",
+            "executable": "${workspaceFolder}/blink.elf",
+            "request": "launch",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "serverpath": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "searchDir": ["${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/scripts"],
+            "gdbPath": "${env:USERPROFILE}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gdb.exe",
+            "device": "RP2350",
+            "configFiles": [
+                "interface/cmsis-dap.cfg",
+                "target/rp2350.cfg"
+            ],
+            "svdFile": "${env:USERPROFILE}/.pico-sdk/sdk/2.2.0/src/rp2350/hardware_regs/RP2350.svd",
+            "overrideLaunchCommands": [
+                "set arch armv8-m.main",
+                "set output-radix 16",
+                "monitor reset init",
+                "load",
+                "monitor reset halt"
+            ],
+            "openOCDPreConfigLaunchCommands": [
+                "set USE_CORE { cm0 cm1 }"
+            ],
+            "openOCDLaunchCommands": [
+                "adapter speed 5000"
+            ],
+            "preLaunchTask": "Compile Project",
+            "showDevDebugOutput": "raw"
+        }
+    ]
+}

drivers/0x02_blink_cbm/.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;${env:USERPROFILE}/.pico-sdk/picotool/2.2.0-a4/picotool;${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-a4/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:${env:HOME}/.pico-sdk/picotool/2.2.0-a4/picotool:${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"
+}

drivers/0x02_blink_cbm/.vscode/tasks.json

@@ -0,0 +1,107 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "shell",
+            "command": ".\\build.bat",
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            },
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc"
+        },
+        {
+            "label": "Clean Project",
+            "type": "shell",
+            "command": ".\\clean.bat",
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": []
+        },
+        {
+            "label": "Run Project",
+            "type": "shell",
+            "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.2.0-a4/picotool/picotool.exe",
+            "args": [
+                "load",
+                "blink.uf2",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "dependsOn": ["Compile Project"]
+        },
+        {
+            "label": "Flash",
+            "type": "shell",
+            "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; program blink.elf verify reset exit"
+            ],
+            "problemMatcher": [],
+            "dependsOn": ["Compile Project"]
+        },
+        {
+            "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"
+            }
+        }
+    ]
+}

drivers/0x02_blink_cbm/blink.c

@@ -0,0 +1,52 @@
+/**
+ * @file blink.c
+ * @brief Implementation of the GPIO output / LED blink driver
+ * @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.
+ */
+
+#include "blink.h"
+#include "gpio.h"
+
+void blink_init(uint32_t pin) {
+    GPIO_Config(pin);
+    GPIO_Clear(pin);
+}
+
+void blink_on(uint32_t pin) {
+    GPIO_Set(pin);
+}
+
+void blink_off(uint32_t pin) {
+    GPIO_Clear(pin);
+}
+
+void blink_toggle(uint32_t pin) {
+    GPIO_Toggle(pin);
+}
+
+bool blink_get_state(uint32_t pin) {
+    return GPIO_Get(pin);
+}

drivers/0x02_blink_cbm/blink.h

@@ -0,0 +1,78 @@
+/**
+ * @file blink.h
+ * @brief Header for GPIO output / LED blink driver
+ * @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.
+ */
+
+#ifndef BLINK_H
+#define BLINK_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/**
+ * @brief Initialize a GPIO pin as a push-pull digital output
+ *
+ * Configures the pad control, sets IO_BANK0 FUNCSEL to SIO, and
+ * enables the output driver. The initial drive level is low (LED off).
+ *
+ * @param pin GPIO pin number to configure as a digital output
+ */
+void blink_init(uint32_t pin);
+
+/**
+ * @brief Drive the output pin high (LED on)
+ *
+ * @param pin GPIO pin number previously initialized with blink_init()
+ */
+void blink_on(uint32_t pin);
+
+/**
+ * @brief Drive the output pin low (LED off)
+ *
+ * @param pin GPIO pin number previously initialized with blink_init()
+ */
+void blink_off(uint32_t pin);
+
+/**
+ * @brief Toggle the current state of the output pin
+ *
+ * Reads the current GPIO output level and inverts it. If the LED was on
+ * it is turned off, and vice versa.
+ *
+ * @param pin GPIO pin number previously initialized with blink_init()
+ */
+void blink_toggle(uint32_t pin);
+
+/**
+ * @brief Query the current drive state of the output pin
+ *
+ * @param pin GPIO pin number previously initialized with blink_init()
+ * @return bool true if the pin is driven high, false if driven low
+ */
+bool blink_get_state(uint32_t pin);
+
+#endif // BLINK_H

drivers/0x02_blink_cbm/build.bat

@@ -0,0 +1,103 @@
+@echo off
+REM ==============================================================================
+REM FILE: build.bat
+REM
+REM DESCRIPTION:
+REM Build script for RP2350 bare-metal C Blink driver.
+REM
+REM BRIEF:
+REM Automates the process of compiling, linking, and generating UF2 firmware.
+REM
+REM AUTHOR: Kevin Thomas
+REM CREATION DATE: 2025
+REM UPDATE DATE: 2025
+REM ==============================================================================
+
+echo Building C bare-metal version...
+
+REM ==============================================================================
+REM Compile C Source Files
+REM ==============================================================================
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c vector_table.c -o vector_table.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c reset_handler.c -o reset_handler.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c stack.c -o stack.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c xosc.c -o xosc.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c reset.c -o reset.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c coprocessor.c -o coprocessor.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c uart.c -o uart.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c gpio.c -o gpio.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c blink.c -o blink.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c delay.c -o delay.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c main.c -o main.o
+if errorlevel 1 goto error
+
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -Og -g3 -Wall -Wextra -ffunction-sections -fdata-sections -c image_def.c -o image_def.o
+if errorlevel 1 goto error
+
+REM ==============================================================================
+REM Link Object Files
+REM ==============================================================================
+arm-none-eabi-gcc -mcpu=cortex-m33 -mthumb -T linker.ld -nostdlib -Wl,--gc-sections vector_table.o reset_handler.o stack.o xosc.o reset.o coprocessor.o uart.o gpio.o blink.o delay.o main.o image_def.o -o blink.elf
+if errorlevel 1 goto error
+
+REM ==============================================================================
+REM Create Raw Binary from ELF
+REM ==============================================================================
+arm-none-eabi-objcopy -O binary blink.elf blink.bin
+if errorlevel 1 goto error
+
+REM ==============================================================================
+REM Create UF2 Image for RP2350
+REM -b 0x10000000 : base address
+REM -f 0xe48bff59 : RP2350 family ID
+REM ==============================================================================
+python uf2conv.py -b 0x10000000 -f 0xe48bff59 -o blink.uf2 blink.bin
+if errorlevel 1 goto error
+
+REM ==============================================================================
+REM Success Message and Flashing Instructions
+REM ==============================================================================
+echo.
+echo =================================
+echo SUCCESS! Created blink.uf2
+echo =================================
+echo.
+echo To flash via UF2:
+echo   1. Hold BOOTSEL button
+echo   2. Plug in USB
+echo   3. Copy blink.uf2 to RP2350 drive
+echo.
+echo To flash via OpenOCD (debug probe):
+echo   openocd -f interface/cmsis-dap.cfg -f target/rp2350.cfg -c "adapter speed 5000" -c "program blink.elf verify reset exit"
+echo.
+goto end
+
+REM ==============================================================================
+REM Error Handling
+REM ==============================================================================
+:error
+echo.
+echo BUILD FAILED!
+echo.
+
+:end

drivers/0x02_blink_cbm/clean.bat

@@ -0,0 +1,30 @@
+@echo off
+REM ==============================================================================
+REM FILE: clean.bat
+REM
+REM DESCRIPTION:
+REM Clean script for RP2350 bare-metal C Blink driver.
+REM
+REM BRIEF:
+REM Removes all build artifacts and generated files.
+REM
+REM AUTHOR: Kevin Thomas
+REM CREATION DATE: 2025
+REM UPDATE DATE: 2025
+REM ==============================================================================
+
+echo Cleaning build artifacts...
+
+REM Remove object files
+if exist *.o del /Q *.o
+
+REM Remove ELF file
+if exist blink.elf del /Q blink.elf
+
+REM Remove binary file
+if exist blink.bin del /Q blink.bin
+
+REM Remove UF2 file
+if exist blink.uf2 del /Q blink.uf2
+
+echo Clean complete!

drivers/0x02_blink_cbm/constants.h

@@ -0,0 +1,214 @@
+/**
+ * @file constants.h
+ * @brief Memory-mapped register structures and peripheral base addresses
+ * @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.
+ */
+
+#ifndef CONSTANTS_H
+#define CONSTANTS_H
+
+#include <stdint.h>
+
+/**
+ * Stack addresses.
+ */
+#define STACK_TOP   0x20082000U
+#define STACK_LIMIT 0x2007A000U
+
+/**
+ * XOSC (External Crystal Oscillator) Register Structure.
+ */
+typedef struct {
+    volatile uint32_t CTRL;        /**< 0x00: Control register */
+    volatile uint32_t STATUS;      /**< 0x04: Status register */
+    volatile uint32_t DORMANT;     /**< 0x08: Dormant mode */
+    volatile uint32_t STARTUP;     /**< 0x0C: Startup delay */
+    volatile uint32_t RESERVED[3]; /**< 0x10-0x18: Reserved */
+    volatile uint32_t COUNT;       /**< 0x1C: Frequency count */
+} xosc_hw_t;
+
+/**
+ * XOSC base address and pointer.
+ */
+#define XOSC_BASE 0x40048000U
+#define XOSC      ((xosc_hw_t *)XOSC_BASE)
+
+/**
+ * XOSC status bit definitions.
+ */
+#define XOSC_STATUS_STABLE_SHIFT 31U
+
+/**
+ * CPACR (Coprocessor Access Control Register) in PPB.
+ */
+#define PPB_BASE 0xE0000000U
+#define CPACR    ((volatile uint32_t *)(PPB_BASE + 0x0ED88U))
+
+/**
+ * Coprocessor access control bit definitions.
+ */
+#define CPACR_CP0_SHIFT 0U
+#define CPACR_CP1_SHIFT 1U
+
+/**
+ * CLOCKS Register Structure.
+ */
+typedef struct {
+    volatile uint32_t RESERVED0[18]; /**< 0x00-0x44: Other clock registers */
+    volatile uint32_t CLK_PERI_CTRL; /**< 0x48: Peripheral clock control */
+} clocks_hw_t;
+
+/**
+ * CLOCKS base address and pointer.
+ */
+#define CLOCKS_BASE 0x40010000U
+#define CLOCKS      ((clocks_hw_t *)CLOCKS_BASE)
+
+/**
+ * Clock control bit definitions.
+ */
+#define CLOCKS_CLK_PERI_CTRL_ENABLE_SHIFT 11U
+#define CLOCKS_CLK_PERI_CTRL_AUXSRC_SHIFT 5U
+#define CLOCKS_CLK_PERI_CTRL_AUXSRC_XOSC  4U
+
+/**
+ * RESETS Register Structure.
+ */
+typedef struct {
+    volatile uint32_t RESET;      /**< 0x00: Reset control */
+    volatile uint32_t WDSEL;      /**< 0x04: Watchdog select */
+    volatile uint32_t RESET_DONE; /**< 0x08: Reset done status */
+} resets_hw_t;
+
+/**
+ * RESETS base address and pointer.
+ */
+#define RESETS_BASE       0x40020000U
+#define RESETS             ((resets_hw_t *)RESETS_BASE)
+#define RESETS_RESET_CLEAR ((volatile uint32_t *)(RESETS_BASE + 0x3000U))
+
+/**
+ * Reset control bit definitions.
+ */
+#define RESETS_RESET_IO_BANK0_SHIFT 6U
+#define RESETS_RESET_UART0_SHIFT    26U
+
+/**
+ * IO_BANK0 GPIO Control Register (one per GPIO).
+ */
+typedef struct {
+    volatile uint32_t STATUS; /**< 0x00: GPIO status */
+    volatile uint32_t CTRL;   /**< 0x04: GPIO control */
+} io_bank0_gpio_ctrl_t;
+
+/**
+ * IO_BANK0 Register Structure.
+ */
+typedef struct {
+    io_bank0_gpio_ctrl_t GPIO[30]; /**< 0x000-0x0E8: GPIO 0-29 */
+} io_bank0_hw_t;
+
+/**
+ * IO_BANK0 base address and pointer.
+ */
+#define IO_BANK0_BASE 0x40028000U
+#define IO_BANK0      ((io_bank0_hw_t *)IO_BANK0_BASE)
+
+/**
+ * GPIO control bit definitions.
+ */
+#define IO_BANK0_CTRL_FUNCSEL_MASK  0x1FU
+#define IO_BANK0_CTRL_FUNCSEL_UART  0x02U
+#define IO_BANK0_CTRL_FUNCSEL_SIO   0x05U
+
+/**
+ * PADS_BANK0 Register Structure.
+ */
+typedef struct {
+    volatile uint32_t VOLTAGE_SELECT; /**< 0x00: Voltage select */
+    volatile uint32_t GPIO[30];       /**< 0x04-0x78: GPIO 0-29 pad control */
+} pads_bank0_hw_t;
+
+/**
+ * PADS_BANK0 base address and pointer.
+ */
+#define PADS_BANK0_BASE 0x40038000U
+#define PADS_BANK0      ((pads_bank0_hw_t *)PADS_BANK0_BASE)
+
+/**
+ * Pad control bit definitions.
+ */
+#define PADS_BANK0_OD_SHIFT  7U
+#define PADS_BANK0_IE_SHIFT  6U
+#define PADS_BANK0_ISO_SHIFT 8U
+
+/**
+ * UART0 base address.
+ */
+#define UART0_BASE 0x40070000U
+
+/**
+ * UART register offsets (as word indices from UART0_BASE).
+ */
+#define UART_DR_OFFSET      (0x00U / 4U)
+#define UART_FR_OFFSET      (0x18U / 4U)
+#define UART_IBRD_OFFSET    (0x24U / 4U)
+#define UART_FBRD_OFFSET    (0x28U / 4U)
+#define UART_LCR_H_OFFSET  (0x2CU / 4U)
+#define UART_CR_OFFSET      (0x30U / 4U)
+
+/**
+ * UART flag register bit definitions.
+ */
+#define UART_FR_TXFF_MASK 32U
+#define UART_FR_RXFE_MASK 16U
+
+/**
+ * UART line control and enable values.
+ */
+#define UART_LCR_H_8N1_FIFO 0x70U
+#define UART_CR_ENABLE       ((3U << 8) | 1U)
+
+/**
+ * GPIO pin definitions.
+ */
+#define LED_PIN 25U
+
+/**
+ * SIO (Single-cycle IO) base address.
+ */
+#define SIO_BASE 0xD0000000U
+
+/**
+ * SIO GPIO output register offsets (as word indices).
+ */
+#define SIO_GPIO_OUT_SET_OFFSET    (0x018U / 4U)
+#define SIO_GPIO_OUT_CLR_OFFSET    (0x020U / 4U)
+#define SIO_GPIO_OUT_XOR_OFFSET    (0x028U / 4U)
+#define SIO_GPIO_OE_SET_OFFSET     (0x038U / 4U)
+#define SIO_GPIO_IN_OFFSET         (0x008U / 4U)
+
+#endif // CONSTANTS_H

drivers/0x02_blink_cbm/coprocessor.c

@@ -0,0 +1,48 @@
+/**
+ * @file coprocessor.c
+ * @brief Coprocessor access control enable 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.
+ */
+
+#include "coprocessor.h"
+#include "constants.h"
+
+void Enable_Coprocessor(void) {
+    uint32_t value;
+
+    // read CPACR value
+    value = *CPACR;
+    // set CP1: Ctrl access priv coproc 1 bit
+    value |= (1U << CPACR_CP1_SHIFT);
+    // set CP0: Ctrl access priv coproc 0 bit
+    value |= (1U << CPACR_CP0_SHIFT);
+    // store value into CPACR
+    *CPACR = value;
+    // data sync barrier
+    __asm__ volatile ("dsb");
+    // instruction sync barrier
+    __asm__ volatile ("isb");
+}

drivers/0x02_blink_cbm/coprocessor.h

@@ -0,0 +1,45 @@
+/**
+ * @file coprocessor.h
+ * @brief Coprocessor access control enable 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.
+ */
+
+#ifndef COPROCESSOR_H
+#define COPROCESSOR_H
+
+/**
+ * @brief Enable coprocessor access via CPACR
+ *
+ * Grants full access to coprocessors 0 and 1 by setting the
+ * corresponding bits in the Coprocessor Access Control Register,
+ * then issues DSB and ISB barriers.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Enable_Coprocessor(void);
+
+#endif // COPROCESSOR_H

drivers/0x02_blink_cbm/delay.c

@@ -0,0 +1,46 @@
+/**
+ * @file delay.c
+ * @brief Millisecond delay functions based on a 14.5 MHz clock
+ * @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.
+ */
+
+#include "delay.h"
+
+void Delay_MS(uint32_t ms) {
+    if (ms == 0) {
+        return;
+    }
+    __asm__ volatile (
+        "mov r4, #3600\n\t"
+        "mul r5, %0, r4\n\t"
+        "1:\n\t"
+        "subs r5, #1\n\t"
+        "bne 1b\n\t"
+        :
+        : "r" (ms)
+        : "r4", "r5", "cc"
+    );
+}

drivers/0x02_blink_cbm/delay.h

@@ -0,0 +1,45 @@
+/**
+ * @file delay.h
+ * @brief Millisecond delay functions based on a 14.5 MHz clock
+ * @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.
+ */
+
+#ifndef DELAY_H
+#define DELAY_H
+
+#include <stdint.h>
+
+/**
+ * @brief Delay for the specified number of milliseconds
+ *
+ * Busy-waits using a calibrated loop count (3600 iterations per ms)
+ * based on a 14.5 MHz clock. Returns immediately if ms is zero.
+ *
+ * @param ms Number of milliseconds to delay
+ */
+void Delay_MS(uint32_t ms);
+
+#endif // DELAY_H

drivers/0x02_blink_cbm/gpio.c

@@ -0,0 +1,111 @@
+/**
+ * @file gpio.c
+ * @brief GPIO configuration, set, clear, toggle, and read 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.
+ */
+
+#include "gpio.h"
+#include "constants.h"
+
+#define SIO ((volatile uint32_t *)SIO_BASE)
+
+/**
+ * @brief Configure pad control for a GPIO pin
+ *
+ * @details Clears OD (output disable), sets IE (input enable), and
+ *          clears ISO (isolation) in PADS_BANK0.
+ *
+ * @param gpio_num GPIO pin number (0-29)
+ */
+static void _gpio_config_pad(uint32_t gpio_num) {
+    uint32_t value;
+
+    // read PAD value
+    value = PADS_BANK0->GPIO[gpio_num];
+    // clear OD bit (output disable)
+    value &= ~(1U << PADS_BANK0_OD_SHIFT);
+    // set IE bit (input enable)
+    value |= (1U << PADS_BANK0_IE_SHIFT);
+    // clear ISO bit (isolate)
+    value &= ~(1U << PADS_BANK0_ISO_SHIFT);
+    // store value into PAD
+    PADS_BANK0->GPIO[gpio_num] = value;
+}
+
+/**
+ * @brief Set IO_BANK0 FUNCSEL to SIO for a GPIO pin
+ *
+ * @details Reads the control register, clears FUNCSEL bits, sets
+ *          FUNCSEL to SIO (0x05), and writes back.
+ *
+ * @param gpio_num GPIO pin number (0-29)
+ */
+static void _gpio_config_funcsel(uint32_t gpio_num) {
+    uint32_t value;
+
+    // read CTRL value
+    value = IO_BANK0->GPIO[gpio_num].CTRL;
+    // clear FUNCSEL bits
+    value &= ~IO_BANK0_CTRL_FUNCSEL_MASK;
+    // set FUNCSEL to SIO (0x05)
+    value |= IO_BANK0_CTRL_FUNCSEL_SIO;
+    // store value into CTRL
+    IO_BANK0->GPIO[gpio_num].CTRL = value;
+}
+
+/**
+ * @brief Enable the output driver for a GPIO pin via SIO
+ *
+ * @details Sets the corresponding bit in the SIO output-enable set
+ *          register.
+ *
+ * @param gpio_num GPIO pin number (0-29)
+ */
+static void _gpio_enable_output(uint32_t gpio_num) {
+    SIO[SIO_GPIO_OE_SET_OFFSET] = (1U << gpio_num);
+}
+
+void GPIO_Config(uint32_t gpio_num) {
+    _gpio_config_pad(gpio_num);
+    _gpio_config_funcsel(gpio_num);
+    _gpio_enable_output(gpio_num);
+}
+
+void GPIO_Set(uint32_t gpio_num) {
+    SIO[SIO_GPIO_OUT_SET_OFFSET] = (1U << gpio_num);
+}
+
+void GPIO_Clear(uint32_t gpio_num) {
+    SIO[SIO_GPIO_OUT_CLR_OFFSET] = (1U << gpio_num);
+}
+
+void GPIO_Toggle(uint32_t gpio_num) {
+    SIO[SIO_GPIO_OUT_XOR_OFFSET] = (1U << gpio_num);
+}
+
+bool GPIO_Get(uint32_t gpio_num) {
+    return (SIO[SIO_GPIO_IN_OFFSET] & (1U << gpio_num)) != 0;
+}

drivers/0x02_blink_cbm/gpio.h

@@ -0,0 +1,86 @@
+/**
+ * @file gpio.h
+ * @brief GPIO configuration, set, clear, toggle, and read 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.
+ */
+
+#ifndef GPIO_H
+#define GPIO_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/**
+ * @brief Configure a GPIO pin as SIO output
+ *
+ * Configures the pad control (clear OD, set IE, clear ISO), sets
+ * IO_BANK0 FUNCSEL to SIO (0x05), and enables the output driver
+ * via the SIO output-enable set register.
+ *
+ * @param gpio_num GPIO pin number (0-29)
+ */
+void GPIO_Config(uint32_t gpio_num);
+
+/**
+ * @brief Drive a GPIO output high
+ *
+ * Sets the specified bit in the SIO GPIO output set register.
+ *
+ * @param gpio_num GPIO pin number (0-29)
+ */
+void GPIO_Set(uint32_t gpio_num);
+
+/**
+ * @brief Drive a GPIO output low
+ *
+ * Sets the specified bit in the SIO GPIO output clear register.
+ *
+ * @param gpio_num GPIO pin number (0-29)
+ */
+void GPIO_Clear(uint32_t gpio_num);
+
+/**
+ * @brief Toggle a GPIO output
+ *
+ * Sets the specified bit in the SIO GPIO output XOR register,
+ * which inverts the current output level.
+ *
+ * @param gpio_num GPIO pin number (0-29)
+ */
+void GPIO_Toggle(uint32_t gpio_num);
+
+/**
+ * @brief Read the current input level of a GPIO pin
+ *
+ * Reads the SIO GPIO input register and returns the state of the
+ * specified pin.
+ *
+ * @param gpio_num GPIO pin number (0-29)
+ * @return bool true if pin is high, false if low
+ */
+bool GPIO_Get(uint32_t gpio_num);
+
+#endif // GPIO_H

drivers/0x02_blink_cbm/image_def.c

@@ -0,0 +1,48 @@
+/**
+ * @file image_def.c
+ * @brief RP2350 IMAGE_DEF block for boot ROM image recognition
+ * @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.
+ */
+
+#include <stdint.h>
+
+/**
+ * IMAGE_DEF block structure placed in flash.
+ * Must appear within the first 4 KB for the boot ROM to accept the image.
+ */
+__attribute__((section(".embedded_block"), used))
+const uint8_t picobin_block[] = {
+    // PICOBIN_BLOCK_MARKER_START (word: 0xffffded3)
+    0xD3, 0xDE, 0xFF, 0xFF,
+    // PICOBIN_BLOCK_ITEM_1BS_IMAGE_TYPE
+    0x42, 0x01, 0x21, 0x10,
+    // PICOBIN_BLOCK_ITEM_2BS_LAST
+    0xFF, 0x01, 0x00, 0x00,
+    // Relative pointer to next block (loop to self)
+    0x00, 0x00, 0x00, 0x00,
+    // PICOBIN_BLOCK_MARKER_END (word: 0xab123579)
+    0x79, 0x35, 0x12, 0xAB
+};

drivers/0x02_blink_cbm/linker.ld

@@ -0,0 +1,106 @@
+/**
+ * @file linker.ld
+ * @brief Minimal linker script for bare-metal RP2350 development
+ * @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.
+ */
+
+ENTRY(Reset_Handler)
+
+/**
+ * Define memory regions.
+ */
+__XIP_BASE   = 0x10000000;
+__XIP_SIZE   = 32M;
+
+__SRAM_BASE  = 0x20000000;
+__SRAM_SIZE  = 512K;
+__STACK_SIZE = 32K;
+
+MEMORY
+{
+  RAM   (rwx) : ORIGIN = __SRAM_BASE, LENGTH = __SRAM_SIZE
+  FLASH (rx)  : ORIGIN = __XIP_BASE,  LENGTH = __XIP_SIZE
+}
+
+/**
+ * Program headers.
+ */
+PHDRS
+{
+  text PT_LOAD FLAGS(5);
+}
+
+/**
+ * Section placement.
+ */
+SECTIONS
+{
+  . = ORIGIN(FLASH);
+
+  /**
+   * Vector table MUST be first at 0x10000000.
+   */
+  .vectors :
+  {
+    KEEP(*(.vectors))
+  } > FLASH :text
+
+  ASSERT((ADDR(.vectors) == ORIGIN(FLASH)),
+         "Vector table must be at start of flash (0x10000000)")
+
+  /**
+   * Text and read-only data.
+   */
+  .text :
+  {
+    . = ALIGN(4);
+    *(.text*)
+    *(.rodata*)
+    KEEP(*(.init))
+    KEEP(*(.fini))
+    KEEP(*(.ARM.attributes))
+  } > FLASH :text
+
+  /**
+   * IMAGE_DEF block at end of code.
+   */
+  .embedded_block :
+  {
+    KEEP(*(.embedded_block))
+  } > FLASH :text
+
+  /**
+   * Non-secure stack symbols.
+   */
+  __StackTop   = ORIGIN(RAM) + LENGTH(RAM);
+  __StackLimit = __StackTop - __STACK_SIZE;
+  __stack      = __StackTop;
+  _stack_top   = __StackTop;
+
+  .stack (NOLOAD) : { . = ALIGN(8); } > RAM
+
+  PROVIDE(__Vectors = ADDR(.vectors));
+}

drivers/0x02_blink_cbm/main.c

@@ -0,0 +1,78 @@
+/**
+ * @file main.c
+ * @brief Blink demonstration: toggle onboard LED every 500 ms
+ * @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 GPIO output control using the blink driver (blink.h / blink.c).
+ * The onboard LED on GPIO 25 is toggled every BLINK_DELAY_MS milliseconds and
+ * the current state is reported over UART.
+ *
+ * Wiring:
+ *   GPIO25 -> Onboard LED (no external wiring needed)
+ */
+
+#include "blink.h"
+#include "uart.h"
+#include "delay.h"
+#include "constants.h"
+
+#define BLINK_DELAY_MS 500
+
+/**
+ * @brief Print the current LED state over UART
+ *
+ * @details Queries the blink driver for the pin state and prints
+ *          "LED: ON\r\n" or "LED: OFF\r\n" over UART0.
+ *
+ * @param pin GPIO pin number to query
+ */
+static void _print_led_state(uint32_t pin) {
+    if (blink_get_state(pin)) {
+        uart_driver_puts("LED: ON\r\n");
+    } else {
+        uart_driver_puts("LED: OFF\r\n");
+    }
+}
+
+/**
+ * @brief Application entry point for the LED blink demo
+ *
+ * Initializes the onboard LED and enters an infinite loop that
+ * toggles the LED state every BLINK_DELAY_MS milliseconds.
+ *
+ * @return int Does not return
+ */
+int main(void) {
+    blink_init(LED_PIN);
+    uart_driver_puts("Blink driver initialized on GPIO 25\r\n");
+    while (1) {
+        blink_toggle(LED_PIN);
+        _print_led_state(LED_PIN);
+        Delay_MS(BLINK_DELAY_MS);
+    }
+}

drivers/0x02_blink_cbm/reset.c

@@ -0,0 +1,45 @@
+/**
+ * @file reset.c
+ * @brief Reset controller functions for subsystem initialization
+ * @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.
+ */
+
+#include "reset.h"
+#include "constants.h"
+
+void Init_Subsystem(void) {
+    uint32_t value;
+
+    // read RESETS->RESET value
+    value = RESETS->RESET;
+    // clear IO_BANK0 bit
+    value &= ~(1U << RESETS_RESET_IO_BANK0_SHIFT);
+    // store value into RESETS->RESET address
+    RESETS->RESET = value;
+    // wait until done
+    while ((RESETS->RESET_DONE & (1U << RESETS_RESET_IO_BANK0_SHIFT)) == 0) {
+    }
+}

drivers/0x02_blink_cbm/reset.h

@@ -0,0 +1,44 @@
+/**
+ * @file reset.h
+ * @brief Reset controller functions for subsystem initialization
+ * @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.
+ */
+
+#ifndef RESET_H
+#define RESET_H
+
+/**
+ * @brief Initialize the IO_BANK0 subsystem by clearing its reset bit
+ *
+ * Clears the IO_BANK0 reset bit in the Reset controller and waits
+ * until the RESET_DONE register confirms the block is out of reset.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Init_Subsystem(void);
+
+#endif // RESET_H

drivers/0x02_blink_cbm/reset_handler.c

@@ -0,0 +1,50 @@
+/**
+ * @file reset_handler.c
+ * @brief Reset handler entry point after power-on or system reset
+ * @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.
+ */
+
+#include "reset_handler.h"
+#include "stack.h"
+#include "xosc.h"
+#include "reset.h"
+#include "uart.h"
+#include "coprocessor.h"
+
+extern int main(void);
+
+void __attribute__((naked, noreturn)) Reset_Handler(void) {
+    __asm__ volatile (
+        "bl Init_Stack\n\t"
+        "bl Init_XOSC\n\t"
+        "bl Enable_XOSC_Peri_Clock\n\t"
+        "bl Init_Subsystem\n\t"
+        "bl UART_Release_Reset\n\t"
+        "bl UART_Init\n\t"
+        "bl Enable_Coprocessor\n\t"
+        "b main\n\t"
+    );
+}

drivers/0x02_blink_cbm/reset_handler.h

@@ -0,0 +1,45 @@
+/**
+ * @file reset_handler.h
+ * @brief Reset handler entry point after power-on or system reset
+ * @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.
+ */
+
+#ifndef RESET_HANDLER_H
+#define RESET_HANDLER_H
+
+/**
+ * @brief Reset handler for the RP2350
+ *
+ * Entry point after reset. Performs stack initialization, XOSC setup,
+ * subsystem reset release, UART initialization, coprocessor enable,
+ * and branches to main().
+ *
+ * @param   None
+ * @retval  None
+ */
+void Reset_Handler(void) __attribute__((noreturn));
+
+#endif // RESET_HANDLER_H

drivers/0x02_blink_cbm/stack.c

@@ -0,0 +1,46 @@
+/**
+ * @file stack.c
+ * @brief Stack pointer initialization for MSP/PSP and their limits
+ * @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.
+ */
+
+#include "stack.h"
+#include "constants.h"
+
+void Init_Stack(void) {
+    __asm__ volatile (
+        "ldr   r0, =%0\n\t"
+        "msr   PSP, r0\n\t"
+        "ldr   r0, =%1\n\t"
+        "msr   MSPLIM, r0\n\t"
+        "msr   PSPLIM, r0\n\t"
+        "ldr   r0, =%0\n\t"
+        "msr   MSP, r0\n\t"
+        :
+        : "i" (STACK_TOP), "i" (STACK_LIMIT)
+        : "r0"
+    );
+}

drivers/0x02_blink_cbm/stack.h

@@ -0,0 +1,44 @@
+/**
+ * @file stack.h
+ * @brief Stack pointer initialization for MSP/PSP and their limits
+ * @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.
+ */
+
+#ifndef STACK_H
+#define STACK_H
+
+/**
+ * @brief Initialize stack pointers
+ *
+ * Sets Main and Process Stack Pointers (MSP/PSP) and their limits
+ * using the STACK_TOP and STACK_LIMIT values from constants.h.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Init_Stack(void);
+
+#endif // STACK_H

drivers/0x02_blink_cbm/uart.c

@@ -0,0 +1,165 @@
+/**
+ * @file uart.c
+ * @brief Implementation of the bare-metal UART0 driver
+ * @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.
+ */
+
+#include "uart.h"
+#include "constants.h"
+
+#define UART_BASE ((volatile uint32_t *)UART0_BASE)
+
+/**
+ * @brief Clear the UART0 reset bit in the reset controller
+ *
+ * @details Reads RESETS->RESET, clears bit 26 (UART0), and writes
+ *          the value back.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_clear_reset_bit(void) {
+    uint32_t value;
+
+    // read RESETS->RESET value
+    value = RESETS->RESET;
+    // clear UART0 reset bit (bit 26)
+    value &= ~(1U << RESETS_RESET_UART0_SHIFT);
+    // write value back to RESETS->RESET
+    RESETS->RESET = value;
+}
+
+/**
+ * @brief Wait until the UART0 block is out of reset
+ *
+ * @details Polls RESETS->RESET_DONE until bit 26 (UART0) is set.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_wait_reset_done(void) {
+    // loop until UART0 is out of reset
+    while ((RESETS->RESET_DONE & (1U << RESETS_RESET_UART0_SHIFT)) == 0) {
+    }
+}
+
+/**
+ * @brief Configure GPIO pins 0 (TX) and 1 (RX) for UART function
+ *
+ * @details Sets IO_BANK0 FUNCSEL to UART (0x02) for both pins and
+ *          programs the corresponding pad controls.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_configure_pins(void) {
+    // FUNCSEL = 2 -> select UART function
+    IO_BANK0->GPIO[0].CTRL = IO_BANK0_CTRL_FUNCSEL_UART;
+    IO_BANK0->GPIO[1].CTRL = IO_BANK0_CTRL_FUNCSEL_UART;
+    // pad config value for TX (pull/func recommended)
+    PADS_BANK0->GPIO[0] = 0x04;
+    // pad config value for RX (input enable)
+    PADS_BANK0->GPIO[1] = 0x40;
+}
+
+/**
+ * @brief Set UART0 baud rate divisors for 115200 baud at 14.5 MHz
+ *
+ * @details Programs UARTIBRD = 6 and UARTFBRD = 33 for the integer
+ *          and fractional baud rate divisors respectively.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_set_baud(void) {
+    // disable UART while configuring
+    UART_BASE[UART_CR_OFFSET] = 0;
+    // set integer baud divisor
+    UART_BASE[UART_IBRD_OFFSET] = 6;
+    // set fractional baud divisor
+    UART_BASE[UART_FBRD_OFFSET] = 33;
+}
+
+/**
+ * @brief Configure line control and enable UART0
+ *
+ * @details Sets 8-bit word length with FIFOs enabled, then enables
+ *          UART0 with both TX and RX.
+ *
+ * @param   None
+ * @retval  None
+ */
+static void _uart_enable(void) {
+    // configure line control: FIFO enable + 8-bit
+    UART_BASE[UART_LCR_H_OFFSET] = UART_LCR_H_8N1_FIFO;
+    // enable UART with TX and RX enabled
+    UART_BASE[UART_CR_OFFSET] = UART_CR_ENABLE;
+}
+
+void UART_Release_Reset(void) {
+    _uart_clear_reset_bit();
+    _uart_wait_reset_done();
+}
+
+void UART_Init(void) {
+    _uart_configure_pins();
+    _uart_set_baud();
+    _uart_enable();
+}
+
+bool uart_driver_is_readable(void) {
+    // test bit 4, RX FIFO empty (RXFE)
+    return (UART_BASE[UART_FR_OFFSET] & UART_FR_RXFE_MASK) == 0;
+}
+
+char uart_driver_getchar(void) {
+    // wait for RX FIFO to be not empty
+    while (UART_BASE[UART_FR_OFFSET] & UART_FR_RXFE_MASK) {
+    }
+    // read data from UARTDR
+    return (char)(UART_BASE[UART_DR_OFFSET] & 0xFF);
+}
+
+void uart_driver_putchar(char c) {
+    // wait for TX FIFO to be not full
+    while (UART_BASE[UART_FR_OFFSET] & UART_FR_TXFF_MASK) {
+    }
+    // write data to UARTDR
+    UART_BASE[UART_DR_OFFSET] = (uint32_t)c;
+}
+
+void uart_driver_puts(const char *str) {
+    while (*str) {
+        uart_driver_putchar(*str++);
+    }
+}
+
+char uart_driver_to_upper(char c) {
+    if (c >= 'a' && c <= 'z') {
+        return (char)(c - 32);
+    }
+    return c;
+}

drivers/0x02_blink_cbm/uart.h

@@ -0,0 +1,111 @@
+/**
+ * @file uart.h
+ * @brief Header for bare-metal UART0 driver (raw TX/RX, GPIO 0/1)
+ * @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.
+ */
+
+#ifndef UART_H
+#define UART_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/**
+ * @brief Release UART0 from reset and wait until it is ready
+ *
+ * Clears the UART0 reset bit in the Reset controller and polls
+ * RESET_DONE until the UART0 block is out of reset.
+ *
+ * @param   None
+ * @retval  None
+ */
+void UART_Release_Reset(void);
+
+/**
+ * @brief Initialize UART0 (pins, baud divisors, line control, enable)
+ *
+ * Configures IO_BANK0 pins 0 (TX) and 1 (RX) to the UART function,
+ * programs pad controls, sets baud rate divisors (IBRD=6, FBRD=33
+ * for 115200 baud at 14.5 MHz), configures 8N1 with FIFOs, and
+ * enables UART0 with TX and RX.
+ *
+ * @param   None
+ * @retval  None
+ */
+void UART_Init(void);
+
+/**
+ * @brief Check whether a received character is waiting in the UART FIFO
+ *
+ * Returns immediately without blocking. Use this to poll for incoming
+ * data before calling uart_driver_getchar().
+ *
+ * @return bool true if at least one byte is available, false otherwise
+ */
+bool uart_driver_is_readable(void);
+
+/**
+ * @brief Read one character from UART0 (blocking)
+ *
+ * Blocks until a byte arrives in the receive FIFO, then returns it.
+ * Prefer pairing with uart_driver_is_readable() to avoid indefinite blocking.
+ *
+ * @return char The received character
+ */
+char uart_driver_getchar(void);
+
+/**
+ * @brief Transmit one character over UART0 (blocking)
+ *
+ * Waits until the transmit FIFO has space, then writes the character
+ * to UARTDR.
+ *
+ * @param c Character to transmit
+ */
+void uart_driver_putchar(char c);
+
+/**
+ * @brief Transmit a null-terminated string over UART0
+ *
+ * Calls uart_driver_putchar() for every character in the string up to
+ * and not including the null terminator.
+ *
+ * @param str Pointer to the null-terminated ASCII string to send
+ */
+void uart_driver_puts(const char *str);
+
+/**
+ * @brief Convert a lowercase ASCII character to uppercase
+ *
+ * Returns the uppercase equivalent if the character is in 'a'-'z';
+ * all other characters are passed through unchanged.
+ *
+ * @param c Input character
+ * @return char Uppercase equivalent, or the original character
+ */
+char uart_driver_to_upper(char c);
+
+#endif // UART_H

drivers/0x02_blink_cbm/uf2conv.py

@@ -0,0 +1,365 @@
+#!/usr/bin/env python3
+import sys
+import struct
+import subprocess
+import re
+import os
+import os.path
+import argparse
+import json
+from time import sleep
+
+
+UF2_MAGIC_START0 = 0x0A324655 # "UF2\n"
+UF2_MAGIC_START1 = 0x9E5D5157 # Randomly selected
+UF2_MAGIC_END    = 0x0AB16F30 # Ditto
+
+INFO_FILE = "/INFO_UF2.TXT"
+
+appstartaddr = 0x2000
+familyid = 0x0
+
+
+def is_uf2(buf):
+    w = struct.unpack("<II", buf[0:8])
+    return w[0] == UF2_MAGIC_START0 and w[1] == UF2_MAGIC_START1
+
+def is_hex(buf):
+    try:
+        w = buf[0:30].decode("utf-8")
+    except UnicodeDecodeError:
+        return False
+    if w[0] == ':' and re.match(rb"^[:0-9a-fA-F\r\n]+$", buf):
+        return True
+    return False
+
+def convert_from_uf2(buf):
+    global appstartaddr
+    global familyid
+    numblocks = len(buf) // 512
+    curraddr = None
+    currfamilyid = None
+    families_found = {}
+    prev_flag = None
+    all_flags_same = True
+    outp = []
+    for blockno in range(numblocks):
+        ptr = blockno * 512
+        block = buf[ptr:ptr + 512]
+        hd = struct.unpack(b"<IIIIIIII", block[0:32])
+        if hd[0] != UF2_MAGIC_START0 or hd[1] != UF2_MAGIC_START1:
+            print("Skipping block at " + ptr + "; bad magic")
+            continue
+        if hd[2] & 1:
+            # NO-flash flag set; skip block
+            continue
+        datalen = hd[4]
+        if datalen > 476:
+            assert False, "Invalid UF2 data size at " + ptr
+        newaddr = hd[3]
+        if (hd[2] & 0x2000) and (currfamilyid == None):
+            currfamilyid = hd[7]
+        if curraddr == None or ((hd[2] & 0x2000) and hd[7] != currfamilyid):
+            currfamilyid = hd[7]
+            curraddr = newaddr
+            if familyid == 0x0 or familyid == hd[7]:
+                appstartaddr = newaddr
+        padding = newaddr - curraddr
+        if padding < 0:
+            assert False, "Block out of order at " + ptr
+        if padding > 10*1024*1024:
+            assert False, "More than 10M of padding needed at " + ptr
+        if padding % 4 != 0:
+            assert False, "Non-word padding size at " + ptr
+        while padding > 0:
+            padding -= 4
+            outp.append(b"\x00\x00\x00\x00")
+        if familyid == 0x0 or ((hd[2] & 0x2000) and familyid == hd[7]):
+            outp.append(block[32 : 32 + datalen])
+        curraddr = newaddr + datalen
+        if hd[2] & 0x2000:
+            if hd[7] in families_found.keys():
+                if families_found[hd[7]] > newaddr:
+                    families_found[hd[7]] = newaddr
+            else:
+                families_found[hd[7]] = newaddr
+        if prev_flag == None:
+            prev_flag = hd[2]
+        if prev_flag != hd[2]:
+            all_flags_same = False
+        if blockno == (numblocks - 1):
+            print("--- UF2 File Header Info ---")
+            families = load_families()
+            for family_hex in families_found.keys():
+                family_short_name = ""
+                for name, value in families.items():
+                    if value == family_hex:
+                        family_short_name = name
+                print("Family ID is {:s}, hex value is 0x{:08x}".format(family_short_name,family_hex))
+                print("Target Address is 0x{:08x}".format(families_found[family_hex]))
+            if all_flags_same:
+                print("All block flag values consistent, 0x{:04x}".format(hd[2]))
+            else:
+                print("Flags were not all the same")
+            print("----------------------------")
+            if len(families_found) > 1 and familyid == 0x0:
+                outp = []
+                appstartaddr = 0x0
+    return b"".join(outp)
+
+def convert_to_carray(file_content):
+    outp = "const unsigned long bindata_len = %d;\n" % len(file_content)
+    outp += "const unsigned char bindata[] __attribute__((aligned(16))) = {"
+    for i in range(len(file_content)):
+        if i % 16 == 0:
+            outp += "\n"
+        outp += "0x%02x, " % file_content[i]
+    outp += "\n};\n"
+    return bytes(outp, "utf-8")
+
+def convert_to_uf2(file_content):
+    global familyid
+    datapadding = b""
+    while len(datapadding) < 512 - 256 - 32 - 4:
+        datapadding += b"\x00\x00\x00\x00"
+    numblocks = (len(file_content) + 255) // 256
+    outp = []
+    for blockno in range(numblocks):
+        ptr = 256 * blockno
+        chunk = file_content[ptr:ptr + 256]
+        flags = 0x0
+        if familyid:
+            flags |= 0x2000
+        hd = struct.pack(b"<IIIIIIII",
+            UF2_MAGIC_START0, UF2_MAGIC_START1,
+            flags, ptr + appstartaddr, 256, blockno, numblocks, familyid)
+        while len(chunk) < 256:
+            chunk += b"\x00"
+        block = hd + chunk + datapadding + struct.pack(b"<I", UF2_MAGIC_END)
+        assert len(block) == 512
+        outp.append(block)
+    return b"".join(outp)
+
+class Block:
+    def __init__(self, addr, default_data=0xFF):
+        self.addr = addr
+        self.bytes = bytearray([default_data] * 256)
+
+    def encode(self, blockno, numblocks):
+        global familyid
+        flags = 0x0
+        if familyid:
+            flags |= 0x2000
+        hd = struct.pack("<IIIIIIII",
+            UF2_MAGIC_START0, UF2_MAGIC_START1,
+            flags, self.addr, 256, blockno, numblocks, familyid)
+        hd += self.bytes[0:256]
+        while len(hd) < 512 - 4:
+            hd += b"\x00"
+        hd += struct.pack("<I", UF2_MAGIC_END)
+        return hd
+
+def convert_from_hex_to_uf2(buf):
+    global appstartaddr
+    appstartaddr = None
+    upper = 0
+    currblock = None
+    blocks = []
+    for line in buf.split('\n'):
+        if line[0] != ":":
+            continue
+        i = 1
+        rec = []
+        while i < len(line) - 1:
+            rec.append(int(line[i:i+2], 16))
+            i += 2
+        tp = rec[3]
+        if tp == 4:
+            upper = ((rec[4] << 8) | rec[5]) << 16
+        elif tp == 2:
+            upper = ((rec[4] << 8) | rec[5]) << 4
+        elif tp == 1:
+            break
+        elif tp == 0:
+            addr = upper + ((rec[1] << 8) | rec[2])
+            if appstartaddr == None:
+                appstartaddr = addr
+            i = 4
+            while i < len(rec) - 1:
+                if not currblock or currblock.addr & ~0xff != addr & ~0xff:
+                    currblock = Block(addr & ~0xff)
+                    blocks.append(currblock)
+                currblock.bytes[addr & 0xff] = rec[i]
+                addr += 1
+                i += 1
+    numblocks = len(blocks)
+    resfile = b""
+    for i in range(0, numblocks):
+        resfile += blocks[i].encode(i, numblocks)
+    return resfile
+
+def to_str(b):
+    return b.decode("utf-8")
+
+def get_drives():
+    drives = []
+    if sys.platform == "win32":
+        r = subprocess.check_output([
+            "powershell",
+            "-Command",
+            '(Get-WmiObject Win32_LogicalDisk -Filter "VolumeName=\'RPI-RP2\'").DeviceID'
+            ])
+        drive = to_str(r).strip()
+        if drive:
+            drives.append(drive)
+    else:
+        searchpaths = ["/mnt", "/media"]
+        if sys.platform == "darwin":
+            searchpaths = ["/Volumes"]
+        elif sys.platform == "linux":
+            searchpaths += ["/media/" + os.environ["USER"], "/run/media/" + os.environ["USER"]]
+            if "SUDO_USER" in os.environ.keys():
+                searchpaths += ["/media/" + os.environ["SUDO_USER"]]
+                searchpaths += ["/run/media/" + os.environ["SUDO_USER"]]
+
+        for rootpath in searchpaths:
+            if os.path.isdir(rootpath):
+                for d in os.listdir(rootpath):
+                    if os.path.isdir(os.path.join(rootpath, d)):
+                        drives.append(os.path.join(rootpath, d))
+
+
+    def has_info(d):
+        try:
+            return os.path.isfile(d + INFO_FILE)
+        except:
+            return False
+
+    return list(filter(has_info, drives))
+
+
+def board_id(path):
+    with open(path + INFO_FILE, mode='r') as file:
+        file_content = file.read()
+    return re.search(r"Board-ID: ([^\r\n]*)", file_content).group(1)
+
+
+def list_drives():
+    for d in get_drives():
+        print(d, board_id(d))
+
+
+def write_file(name, buf):
+    with open(name, "wb") as f:
+        f.write(buf)
+    print("Wrote %d bytes to %s" % (len(buf), name))
+
+
+def load_families():
+    # The expectation is that the `uf2families.json` file is in the same
+    # directory as this script. Make a path that works using `__file__`
+    # which contains the full path to this script.
+    filename = "uf2families.json"
+    pathname = os.path.join(os.path.dirname(os.path.abspath(__file__)), filename)
+    with open(pathname) as f:
+        raw_families = json.load(f)
+
+    families = {}
+    for family in raw_families:
+        families[family["short_name"]] = int(family["id"], 0)
+
+    return families
+
+
+def main():
+    global appstartaddr, familyid
+    def error(msg):
+        print(msg, file=sys.stderr)
+        sys.exit(1)
+    parser = argparse.ArgumentParser(description='Convert to UF2 or flash directly.')
+    parser.add_argument('input', metavar='INPUT', type=str, nargs='?',
+                        help='input file (HEX, BIN or UF2)')
+    parser.add_argument('-b', '--base', dest='base', type=str,
+                        default="0x2000",
+                        help='set base address of application for BIN format (default: 0x2000)')
+    parser.add_argument('-f', '--family', dest='family', type=str,
+                        default="0x0",
+                        help='specify familyID - number or name (default: 0x0)')
+    parser.add_argument('-o', '--output', metavar="FILE", dest='output', type=str,
+                        help='write output to named file; defaults to "flash.uf2" or "flash.bin" where sensible')
+    parser.add_argument('-d', '--device', dest="device_path",
+                        help='select a device path to flash')
+    parser.add_argument('-l', '--list', action='store_true',
+                        help='list connected devices')
+    parser.add_argument('-c', '--convert', action='store_true',
+                        help='do not flash, just convert')
+    parser.add_argument('-D', '--deploy', action='store_true',
+                        help='just flash, do not convert')
+    parser.add_argument('-w', '--wait', action='store_true',
+                        help='wait for device to flash')
+    parser.add_argument('-C', '--carray', action='store_true',
+                        help='convert binary file to a C array, not UF2')
+    parser.add_argument('-i', '--info', action='store_true',
+                        help='display header information from UF2, do not convert')
+    args = parser.parse_args()
+    appstartaddr = int(args.base, 0)
+
+    families = load_families()
+
+    if args.family.upper() in families:
+        familyid = families[args.family.upper()]
+    else:
+        try:
+            familyid = int(args.family, 0)
+        except ValueError:
+            error("Family ID needs to be a number or one of: " + ", ".join(families.keys()))
+
+    if args.list:
+        list_drives()
+    else:
+        if not args.input:
+            error("Need input file")
+        with open(args.input, mode='rb') as f:
+            inpbuf = f.read()
+        from_uf2 = is_uf2(inpbuf)
+        ext = "uf2"
+        if args.deploy:
+            outbuf = inpbuf
+        elif from_uf2 and not args.info:
+            outbuf = convert_from_uf2(inpbuf)
+            ext = "bin"
+        elif from_uf2 and args.info:
+            outbuf = ""
+            convert_from_uf2(inpbuf)
+        elif is_hex(inpbuf):
+            outbuf = convert_from_hex_to_uf2(inpbuf.decode("utf-8"))
+        elif args.carray:
+            outbuf = convert_to_carray(inpbuf)
+            ext = "h"
+        else:
+            outbuf = convert_to_uf2(inpbuf)
+        if not args.deploy and not args.info:
+            print("Converted to %s, output size: %d, start address: 0x%x" %
+                  (ext, len(outbuf), appstartaddr))
+        if args.convert or ext != "uf2":
+            if args.output == None:
+                args.output = "flash." + ext
+        if args.output:
+            write_file(args.output, outbuf)
+        if ext == "uf2" and not args.convert and not args.info:
+            drives = get_drives()
+            if len(drives) == 0:
+                if args.wait:
+                    print("Waiting for drive to deploy...")
+                    while len(drives) == 0:
+                        sleep(0.1)
+                        drives = get_drives()
+                elif not args.output:
+                    error("No drive to deploy.")
+            for d in drives:
+                print("Flashing %s (%s)" % (d, board_id(d)))
+                write_file(d + "/NEW.UF2", outbuf)
+
+
+if __name__ == "__main__":
+    main()

drivers/0x02_blink_cbm/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"
+    }
+]

drivers/0x02_blink_cbm/vector_table.c

@@ -0,0 +1,46 @@
+/**
+ * @file vector_table.c
+ * @brief Vector table with initial stack pointer and reset handler
+ * @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.
+ */
+
+#include <stdint.h>
+
+extern uint32_t _stack_top;
+extern void Reset_Handler(void);
+
+typedef void (*vector_func_t)(void);
+
+/**
+ * Vector table placed in .vectors section.
+ * The Thumb bit (bit 0 = 1) is automatically set by the linker
+ * for function pointers in Thumb mode.
+ */
+__attribute__((section(".vectors"), used))
+const void *_vectors[2] = {
+    &_stack_top,
+    Reset_Handler
+};

drivers/0x02_blink_cbm/xosc.c

@@ -0,0 +1,54 @@
+/**
+ * @file xosc.c
+ * @brief External crystal oscillator (XOSC) initialization and clock enable
+ * @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.
+ */
+
+#include "xosc.h"
+#include "constants.h"
+
+void Init_XOSC(void) {
+    // set delay 50,000 cycles
+    XOSC->STARTUP = 0x00C4U;
+    // set 1_15MHz, freq range, actual 14.5MHz
+    XOSC->CTRL = 0x00FABAA0U;
+    // wait until stable bit is set
+    while ((XOSC->STATUS & (1U << XOSC_STATUS_STABLE_SHIFT)) == 0) {
+    }
+}
+
+void Enable_XOSC_Peri_Clock(void) {
+    uint32_t value;
+
+    // read CLK_PERI_CTRL value
+    value = CLOCKS->CLK_PERI_CTRL;
+    // set ENABLE bit
+    value |= (1U << CLOCKS_CLK_PERI_CTRL_ENABLE_SHIFT);
+    // set AUXSRC: XOSC_CLKSRC
+    value |= (CLOCKS_CLK_PERI_CTRL_AUXSRC_XOSC << CLOCKS_CLK_PERI_CTRL_AUXSRC_SHIFT);
+    // store value into CLK_PERI_CTRL
+    CLOCKS->CLK_PERI_CTRL = value;
+}

drivers/0x02_blink_cbm/xosc.h

@@ -0,0 +1,55 @@
+/**
+ * @file xosc.h
+ * @brief External crystal oscillator (XOSC) initialization and clock enable
+ * @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.
+ */
+
+#ifndef XOSC_H
+#define XOSC_H
+
+/**
+ * @brief Initialize the external crystal oscillator and wait until stable
+ *
+ * Configures the XOSC startup delay and frequency range, then polls
+ * the status register until the STABLE bit is set.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Init_XOSC(void);
+
+/**
+ * @brief Enable the XOSC peripheral clock
+ *
+ * Sets the peripheral clock to use XOSC as its auxiliary source and
+ * enables it via CLK_PERI_CTRL.
+ *
+ * @param   None
+ * @retval  None
+ */
+void Enable_XOSC_Peri_Clock(void);
+
+#endif // XOSC_H