[Grbl] is a no-compromise, high performance, low cost alternative
to parallel-port-based motion control for CNC milling. This version
of Grbl runs on an Arduino with a 328p processor (Uno, Duemilanove,
Nano, Micro, etc). The controller is written in highly optimized C utilizing every clever feature of the AVR-chips to achieve precise timing and asynchronous operation. It is able to maintain up to 30kHz of stable, jitter free control pulses.
https://github.com/gnea/grbl