Added final chapters

0x0026_functions/.gitignore

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

0x0026_functions/.vscode/c_cpp_properties.json

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

0x0026_functions/.vscode/cmake-kits.json

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

0x0026_functions/.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"
+    ]
+}

0x0026_functions/.vscode/launch.json

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

0x0026_functions/.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"
+}

0x0026_functions/.vscode/tasks.json

@@ -0,0 +1,102 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Compile Project",
+            "type": "process",
+            "isBuildCommand": true,
+            "command": "${userHome}/.pico-sdk/ninja/v1.12.1/ninja",
+            "args": ["-C", "${workspaceFolder}/build"],
+            "group": "build",
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": "$gcc",
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/ninja/v1.12.1/ninja.exe"
+            }
+        },
+        {
+            "label": "Run Project",
+            "type": "process",
+            "command": "${env:HOME}/.pico-sdk/picotool/2.2.0-a4/picotool/picotool",
+            "args": [
+                "load",
+                "${command:raspberry-pi-pico.launchTargetPath}",
+                "-fx"
+            ],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated"
+            },
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/picotool/2.2.0-a4/picotool/picotool.exe"
+            }
+        },
+        {
+            "label": "Flash",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getTarget}.cfg",
+                "-c",
+                "adapter speed 5000; program \"${command:raspberry-pi-pico.launchTargetPath}\" verify reset exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "Rescue Reset",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/${command:raspberry-pi-pico.getChip}-rescue.cfg",
+                "-c",
+                "adapter speed 5000; reset halt; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        },
+        {
+            "label": "RISC-V Reset (RP2350)",
+            "type": "process",
+            "command": "${userHome}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            "args": [
+                "-s",
+                "${userHome}/.pico-sdk/openocd/0.12.0+dev/scripts",
+                "-c",
+                "set USE_CORE { rv0 rv1 cm0 cm1 }",
+                "-f",
+                "interface/cmsis-dap.cfg",
+                "-f",
+                "target/rp2350.cfg",
+                "-c",
+                "adapter speed 5000; init;",
+                "-c",
+                "write_memory 0x40120158 8 { 0x3 }; echo [format \"Info : ARCHSEL 0x%02x\" [read_memory 0x40120158 8 1]];",
+                "-c",
+                "reset halt; targets rp2350.rv0; echo [format \"Info : ARCHSEL_STATUS 0x%02x\" [read_memory 0x4012015C 8 1]]; exit"
+            ],
+            "problemMatcher": [],
+            "windows": {
+                "command": "${env:USERPROFILE}/.pico-sdk/openocd/0.12.0+dev/openocd.exe",
+            }
+        }
+    ]
+}

0x0026_functions/0x0026_functions.c

@@ -0,0 +1,149 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include "pico/stdlib.h"
+#include "ir.h"
+
+#define IR_PIN 5
+
+typedef struct {
+    uint8_t led1_pin;
+    uint8_t led2_pin;
+    uint8_t led3_pin;
+    bool led1_state;
+    bool led2_state;
+    bool led3_state;
+} simple_led_ctrl_t;
+
+/**
+ * @brief Map NEC IR command code to LED number
+ *
+ * Translates a received NEC IR command code to a logical LED number.
+ * Supports three button mappings for controlling individual LEDs.
+ *
+ * @param ir_command NEC command code from IR receiver
+ * @return int LED number (1-3) or 0 if no match
+ */
+int ir_to_led_number(int ir_command) {
+    if (ir_command == 0x0C) return 1;
+    if (ir_command == 0x18) return 2;
+    if (ir_command == 0x5E) return 3;
+    return 0;
+}
+
+/**
+ * @brief Get GPIO pin number for a given LED number
+ *
+ * Retrieves the GPIO pin associated with a logical LED number
+ * from the LED controller structure.
+ *
+ * @param leds Pointer to LED controller structure
+ * @param led_num LED number (1-3)
+ * @return uint8_t GPIO pin number or 0 if invalid
+ */
+uint8_t get_led_pin(simple_led_ctrl_t *leds, int led_num) {
+    if (led_num == 1) return leds->led1_pin;
+    if (led_num == 2) return leds->led2_pin;
+    if (led_num == 3) return leds->led3_pin;
+    return 0;
+}
+
+/**
+ * @brief Turn off all LEDs in the controller
+ *
+ * Sets all three LED GPIO outputs to low, turning off all LEDs.
+ *
+ * @param leds Pointer to LED controller structure
+ */
+void leds_all_off(simple_led_ctrl_t *leds) {
+    gpio_put(leds->led1_pin, false);
+    gpio_put(leds->led2_pin, false);
+    gpio_put(leds->led3_pin, false);
+}
+
+/**
+ * @brief Blink an LED pin a specified number of times
+ *
+ * Toggles the specified GPIO pin on and off for the given count,
+ * with configurable delay between transitions.
+ *
+ * @param pin GPIO pin number to blink
+ * @param count Number of blink cycles
+ * @param delay_ms Delay in milliseconds for on/off periods
+ */
+void blink_led(uint8_t pin, uint8_t count, uint32_t delay_ms) {
+    for (uint8_t i = 0; i < count; i++) {
+        gpio_put(pin, true);
+        sleep_ms(delay_ms);
+        gpio_put(pin, false);
+        sleep_ms(delay_ms);
+    }
+}
+
+/**
+ * @brief Process IR command and activate corresponding LED
+ *
+ * Handles incoming IR commands by turning off all LEDs, mapping the
+ * command to an LED, blinking it, then holding it steady.
+ *
+ * @param ir_command NEC command code from IR receiver
+ * @param leds Pointer to LED controller structure
+ * @param blink_count Number of blinks before steady state
+ * @return int LED number activated (1-3), 0 if none, -1 if invalid
+ */
+int process_ir_led_command(int ir_command, simple_led_ctrl_t *leds, uint8_t blink_count) {
+    if (!leds || ir_command < 0) return -1;
+    leds_all_off(leds);
+    int led_num = ir_to_led_number(ir_command);
+    if (led_num == 0) return 0;
+    uint8_t pin = get_led_pin(leds, led_num);
+    blink_led(pin, blink_count, 50);
+    gpio_put(pin, true);
+    return led_num;
+}
+
+int main(void) {
+    stdio_init_all();
+
+    simple_led_ctrl_t leds = {
+        .led1_pin = 16,
+        .led2_pin = 17,
+        .led3_pin = 18,
+        .led1_state = false,
+        .led2_state = false,
+        .led3_state = false
+    };
+
+    // Initialize LED GPIOs
+    gpio_init(leds.led1_pin); gpio_set_dir(leds.led1_pin, GPIO_OUT);
+    gpio_init(leds.led2_pin); gpio_set_dir(leds.led2_pin, GPIO_OUT);
+    gpio_init(leds.led3_pin); gpio_set_dir(leds.led3_pin, GPIO_OUT);
+
+    // Initialize IR receiver
+    ir_init(IR_PIN);
+    printf("IR receiver on GPIO %d ready\n", IR_PIN);
+    printf("Press remote buttons to control LEDs with blink effects!\n");
+
+    while (true) {
+        int key = ir_getkey();
+        if (key >= 0) {
+            printf("NEC command: 0x%02X\n", key);
+
+            // Process the IR command with 3 blinks before steady state
+            int activated_led = process_ir_led_command(key, &leds, 3);
+
+            if (activated_led > 0) {
+                printf("LED %d activated on GPIO %d\n", activated_led,
+                       (activated_led == 1) ? leds.led1_pin :
+                       (activated_led == 2) ? leds.led2_pin : leds.led3_pin);
+            } else if (activated_led == 0) {
+                printf("No LED matched or chase effect played\n");
+            } else {
+                printf("Invalid command or null pointer\n");
+            }
+
+            sleep_ms(10);
+        } else {
+            sleep_ms(1);
+        }
+    }
+}

0x0026_functions/CMakeLists.txt

@@ -0,0 +1,57 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.2.0)
+set(toolchainVersion 14_2_Rel1)
+set(picotoolVersion 2.2.0-a4)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico2 CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(0x0026_functions C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(0x0026_functions 0x0026_functions.c ir.c)
+
+pico_set_program_name(0x0026_functions "0x0026_functions")
+pico_set_program_version(0x0026_functions "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(0x0026_functions 1)
+pico_enable_stdio_usb(0x0026_functions 0)
+
+# Add the standard library to the build
+target_link_libraries(0x0026_functions
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(0x0026_functions PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+pico_add_extra_outputs(0x0026_functions)
+

0x0026_functions/ir.c

@@ -0,0 +1,80 @@
+/**
+ * @file ir.c
+ * @brief Implementation of NEC IR receiver (decoder)
+ * @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 "ir.h"
+#include "pico/stdlib.h"
+#include "pico/time.h"
+#include "hardware/gpio.h"
+
+static unsigned int ir_pin = 0;
+
+// Wait for 'gpio' to reach 'level' or timeout (microseconds). Return elapsed us or -1.
+static int64_t wait_for_level(unsigned int gpio, bool level, uint32_t timeout_us) {
+    absolute_time_t start = get_absolute_time();
+    while (gpio_get(gpio) != level) {
+        if (absolute_time_diff_us(start, get_absolute_time()) > (int64_t)timeout_us) {
+            return -1;
+        }
+    }
+    return absolute_time_diff_us(start, get_absolute_time());
+}
+
+void ir_init(uint8_t pin) {
+    ir_pin = pin;
+    gpio_init(pin);
+    gpio_set_dir(pin, GPIO_IN);
+    gpio_pull_up(pin);
+}
+
+int ir_getkey(void) {
+    // leader low (~9 ms)
+    if (wait_for_level(ir_pin, 0, 150000) < 0) return -1;
+
+    int64_t t = wait_for_level(ir_pin, 1, 12000);
+    if (t < 8000 || t > 10000) return -1;
+
+    t = wait_for_level(ir_pin, 0, 7000);
+    if (t < 3500 || t > 5000) return -1;
+
+    uint8_t data[4] = {0, 0, 0, 0};
+    for (int i = 0; i < 32; ++i) {
+        if (wait_for_level(ir_pin, 1, 1000) < 0) return -1;
+        t = wait_for_level(ir_pin, 0, 2500);
+        if (t < 200) return -1;
+        int byte_idx = i / 8;
+        int bit_idx = i % 8;
+        if (t > 1200) data[byte_idx] |= (1 << bit_idx); // logical '1'
+    }
+
+    // Validate address/data inverted pairs
+    if ((uint8_t)(data[0] + data[1]) == 0xFF && (uint8_t)(data[2] + data[3]) == 0xFF) {
+        return data[2];
+    }
+    return -1;
+}

0x0026_functions/ir.h

@@ -0,0 +1,63 @@
+/**
+ * @file ir.h
+ * @brief Header for NEC IR receiver (decoder) API
+ * @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 IR_H
+#define IR_H
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Initialize the IR receiver GPIO
+ *
+ * Configures the given `pin` as an input with pull-up for the NEC IR receiver.
+ * Call this once during board initialization before calling `ir_getkey()`.
+ *
+ * @param pin GPIO pin number connected to IR receiver output
+ */
+void ir_init(uint8_t pin);
+
+/**
+ * @brief Blocking NEC IR decoder
+ *
+ * Blocks while waiting for a complete NEC frame. On success returns the
+ * decoded command byte (0..255). On timeout or protocol error returns -1.
+ *
+ * @return decoded command byte (0..255) or -1 on failure
+ */
+int ir_getkey(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // IR_H

0x0026_functions/pico_sdk_import.cmake

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