This is a framework for using the Raspberry Pi running Raspberry Pi OS or another standard Linux distribution as an embedded microcontroller.
See also the Linux Simple I/O Library, which supports all Raspberry Pi models.
See also MuntsOS Embedded Linux, which supports all Raspberry Pi models, and may be better for embedded applications.
The source code is available at: http://git.munts.com/rpi-mcu
Use the following command to clone it:
git clone http://git.munts.com/rpi-mcu.git