initial example

This commit is contained in:
Adolfo Reyna
2025-11-17 23:34:35 -05:00
commit fe2b2c2e2b
10 changed files with 552 additions and 0 deletions

2
.gitignore vendored Normal file
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build
!.vscode/*

22
.vscode/c_cpp_properties.json vendored Normal file
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{
"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": "${userHome}/.pico-sdk/toolchain/14_2_Rel1/bin/arm-none-eabi-gcc",
"compileCommands": "${workspaceFolder}/build/compile_commands.json",
"cStandard": "c17",
"cppStandard": "c++14",
"intelliSenseMode": "linux-gcc-arm"
}
],
"version": 4
}

15
.vscode/cmake-kits.json vendored Normal file
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[
{
"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}"
}
}
]

9
.vscode/extensions.json vendored Normal file
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{
"recommendations": [
"marus25.cortex-debug",
"ms-vscode.cpptools",
"ms-vscode.cpptools-extension-pack",
"ms-vscode.vscode-serial-monitor",
"raspberry-pi.raspberry-pi-pico"
]
}

50
.vscode/launch.json vendored Normal file
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{
"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}\""
]
},
]
}

40
.vscode/settings.json vendored Normal file
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{
"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"
}

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.vscode/tasks.json vendored Normal file
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{
"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",
}
}
]
}

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CMakeLists.txt Normal file
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# 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 pico_w CACHE STRING "Board type")
# Pull in Raspberry Pi Pico SDK (must be before project)
include(pico_sdk_import.cmake)
project(hello_usb C CXX ASM)
# Initialise the Raspberry Pi Pico SDK
pico_sdk_init()
# Add executable. Default name is the project name, version 0.1
if (TARGET tinyusb_device)
add_executable(hello_usb
hello_usb.c
)
# pull in common dependencies
target_link_libraries(hello_usb pico_stdlib)
# enable usb output, disable uart output
pico_enable_stdio_usb(hello_usb 1)
pico_enable_stdio_uart(hello_usb 0)
# create map/bin/hex/uf2 file etc.
pico_add_extra_outputs(hello_usb)
# add url via pico_set_program_url
elseif(PICO_ON_DEVICE)
message("Skipping hello_usb because TinyUSB submodule is not initialized in the SDK")
endif()

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hello_usb.c Normal file
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/**
* Simple USB Serial Echo Program with Timeout, Reconnect, and Backspace Logic.
* This program now correctly handles the backspace character by deleting it
* from the buffer and sending the necessary control codes to the terminal
* for visual deletion.
*/
#include "pico/stdlib.h"
#include "pico/time.h" // Needed for time_us_64()
#include <stdio.h>
#include <ctype.h>
// Define the maximum size for the input string buffer
#define MAX_INPUT_LEN 64
// Define the timeout period: 1 second in microseconds
#define TIMEOUT_US 5000000
// ASCII code for Backspace (often sent as 0x08)
#define ASCII_BACKSPACE 8
// Helper function to handle the echoing and resetting of the buffer
void echo_and_reset(char* buffer, int* index_ptr) {
if (*index_ptr > 0) {
// Null-terminate the string
buffer[*index_ptr] = '\0';
// Echo the string back, converting to uppercase
printf("\nEchoed (ALL CAPS): ");
for (int i = 0; buffer[i] != '\0'; i++) {
printf("%c", toupper(buffer[i]));
}
printf("\n");
}
// Reset buffer for next line and print a new prompt
*index_ptr = 0;
printf("> ");
}
// Function to handle the initial waiting and reconnect waiting
void wait_for_usb_connection() {
printf("Waiting for USB host to connect...\n");
// Wait until the USB host (e.g., terminal program) opens the serial port
while (!stdio_usb_connected()) {
sleep_ms(100);
}
// Connection established!
printf("\nConnection Established! Starting Echo Session...\n");
}
void run_echo_session() {
char input_buffer[MAX_INPUT_LEN];
int buffer_index = 0;
// Track the time (in microseconds) when the last character was received
uint64_t last_char_time = time_us_64();
printf("--- Pico USB String Echo Program Started ---\n");
printf("Type a sentence (up to %d chars). It will echo on Enter/Timeout.\n", MAX_INPUT_LEN - 2);
printf("--------------------------------------------\n");
printf("> "); // Prompt for input
// Inner loop runs ONLY while the USB connection is active
while (stdio_usb_connected()) {
// Check for incoming character without blocking
int c = getchar_timeout_us(0);
if (c != PICO_ERROR_TIMEOUT) {
// Character received, update the timer
last_char_time = time_us_64();
char input_char = (char)c;
// 1. --- BACKSPACE HANDLING ---
if (input_char == ASCII_BACKSPACE || input_char == 127) { // 127 is sometimes sent by terminals (DEL key)
if (buffer_index > 0) {
// Decrease buffer index (remove the character)
buffer_index--;
// Send backspace, space, and backspace to erase the character on the terminal:
// \b: move cursor back
// ' ': overwrite with a space
// \b: move cursor back again, ready for the next character
printf("\b \b");
}
// 2. --- End of Input (Newline/CR) ---
} else if (input_char == '\r' || input_char == '\n') {
echo_and_reset(input_buffer, &buffer_index);
// 3. --- Collect regular characters ---
} else if (buffer_index < (MAX_INPUT_LEN - 1) && isprint(input_char)) {
// Echo character locally so the user sees what they type
printf("%c", input_char);
// Store character in the buffer
input_buffer[buffer_index] = input_char;
buffer_index++;
}
// Ignore non-printable characters and overflowed buffer input
}
// 4. Timeout Check
if (buffer_index > 0 && (time_us_64() - last_char_time) > TIMEOUT_US) {
printf("\n--- Timeout Reached (5.0s silence) ---\n");
echo_and_reset(input_buffer, &buffer_index);
last_char_time = time_us_64(); // Reset time to prevent immediate re-trigger
}
// Add a small delay to prevent the loop from consuming too much CPU time
sleep_us(100);
}
// Connection lost or closed by host
printf("\nHost disconnected. Ending Echo Session.\n");
}
int main() {
// Initialize Standard I/O (stdio) to use the USB backend
stdio_init_all();
// Outer loop: Allows the program to run continuously and restart the
// session after a disconnection.
while (true) {
// 1. Wait for a connection
wait_for_usb_connection();
// 2. Run the program logic while connected
run_echo_session();
// Loop repeats, going back to wait_for_usb_connection()
}
// Note: main should not return
}

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pico_sdk_import.cmake Normal file
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# 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})