The full documentation is at https://remora-docs.readthedocs.io/en/latest/
Remora is a free, opensource LinuxCNC component and Programmable Realtime Unit (PRU) firmware to allow LPC17xx micro-controller "Smoothieboard" compatible controller boards to be used in conjuction with a Raspberry Pi to implement a LinuxCNC based CNC controller.
Having a low cost and accessable hardware platform for LinuxCNC is important if we want to use LinuxCNC for 3D printing for example. Having a controller box the size of the printer itself makes no sense in this applicatoin. A SoC based single board computer is ideal in this application. Although developed for 3D Printing, Remora (and LinuxCNC) is highly flexible and configurable for other CNC applications.
Remora has been in use amd development since 2017. Starting on Raspberry Pi 3B and 3B+ eventhough at the time it was percieved that the Raspberry Pi was not a viable hardware for LinuxCNC.
With the release of the RPi 4 the LinuxCNC community now supports the hardware, with LinuxCNC and Preempt-RT Kernel packages now available from the LinuxCNC repository. This now greatly simplifies the build of a Raspberry Pi based CNC controller.