portable/ThirdParty/GCC/RP2040/README.md - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 ## Overview

 This directory provides an SMP FreeRTOS-Kernel port that can be used with the Raspberry Pi Pico SDK. It supports:

  * Simple CMake INTERFACE libraries, to provide the FreeRTOS-Kernel and also the individual allocator types, without copying code into the user's project.
  * Running the FreeRTOS-Kernel and tasks on either core 0 or core 1, or both.
  * Use of SDK synchronization primitives (such as mutexes, semaphores, queues from pico_sync) between FreeRTOS tasks and code executing on a non FreeRTOS core, or in IRQ handlers.

 Note that whilst this SMP version can be run on just a single (either) core, it is probably
 more efficient to use the non SMP version in the main FreeRTOS-Kernel branch in that case.

 ## Using this port

 You can copy [FreeRTOS_Kernel_import.cmake](FreeRTOS_Kernel_import.cmake) into your project, and
 add the following in your `CMakeLists.txt`:

 ```cmake
 include(FreeRTOS_Kernel_import.cmake)
 ```

 This will locate the FreeRTOS kernel if it is a direct sub-module of your project, or if you provide the
 `FREERTOS_KERNEL_PATH` variable in your environment or via `-DFREERTOS_KERNEL_PATH=/path/to/FreeRTOS-Kernel` on the CMake command line.

 **NOTE:** If you are using version 1.3.1 or older of the Raspberry Pi Pico SDK then this line must appear before the
 `pico_sdk_init()` and will cause FreeRTOS to be included/required in all RP2040 targets in your project. After this SDK
 version, you can include the FreeRTOS-Kernel support later in your CMake build (possibly in a subdirectory) and the
 FreeRTOS-Kernel support will only apply to those targets which explicitly include FreeRTOS support.

 As an alternative to the `import` statement above, you can just add this directory directly via the following (with
 the same placement restrictions related to the Raspberry Pi Pico SDK version above):

 ```cmake
 add_subdirectory(path/to/this/directory FreeRTOS-Kernel)
 ```


 ## Advanced Configuration

 Some additional `config` options are defined [here](include/rp2040_config.h) which control some low level implementation details.

 ## Known Limitations

 - Tickless idle has not currently been tested, and is likely non-functional
	## Overview

	This directory provides an SMP FreeRTOS-Kernel port that can be used with the Raspberry Pi Pico SDK. It supports:

	* Simple CMake INTERFACE libraries, to provide the FreeRTOS-Kernel and also the individual allocator types, without copying code into the user's project.
	* Running the FreeRTOS-Kernel and tasks on either core 0 or core 1, or both.
	* Use of SDK synchronization primitives (such as mutexes, semaphores, queues from pico_sync) between FreeRTOS tasks and code executing on a non FreeRTOS core, or in IRQ handlers.

	Note that whilst this SMP version can be run on just a single (either) core, it is probably
	more efficient to use the non SMP version in the main FreeRTOS-Kernel branch in that case.

	## Using this port

	You can copy [FreeRTOS_Kernel_import.cmake](FreeRTOS_Kernel_import.cmake) into your project, and
	add the following in your `CMakeLists.txt`:

	```cmake
	include(FreeRTOS_Kernel_import.cmake)
	```

	This will locate the FreeRTOS kernel if it is a direct sub-module of your project, or if you provide the
	`FREERTOS_KERNEL_PATH` variable in your environment or via `-DFREERTOS_KERNEL_PATH=/path/to/FreeRTOS-Kernel` on the CMake command line.

	NOTE: If you are using version 1.3.1 or older of the Raspberry Pi Pico SDK then this line must appear before the
	`pico_sdk_init()` and will cause FreeRTOS to be included/required in all RP2040 targets in your project. After this SDK
	version, you can include the FreeRTOS-Kernel support later in your CMake build (possibly in a subdirectory) and the
	FreeRTOS-Kernel support will only apply to those targets which explicitly include FreeRTOS support.

	As an alternative to the `import` statement above, you can just add this directory directly via the following (with
	the same placement restrictions related to the Raspberry Pi Pico SDK version above):

	```cmake
	add_subdirectory(path/to/this/directory FreeRTOS-Kernel)
	```


	## Advanced Configuration

	Some additional `config` options are defined [here](include/rp2040_config.h) which control some low level implementation details.

	## Known Limitations

	- Tickless idle has not currently been tested, and is likely non-functional