I’ve fixed a problem with Grbl Controller where it expected Grbl to reset upon serial port open – some devices like the AlaMode initialize once and when you connect, there is no version response. The fix involved sending a Ctrl-X if no response was detected.
The AlaMode is an Arduino-compatible board that stacks on top of the Raspberry Pi and communicates serially through the GPIO bus.
Checkout my writeup on getting the AlaMode running with Grbl
You can pick one up at MakerShed