This example is intended as a starting point for creating custom firmware for the CNC Shield with A4988 stepper motor drivers. It includes a simple ASCII protocol for sending motion commands to ease connecting to dynamic code (e.g. Python) running on a laptop or Raspberry Pi. It is a fork of OneInOneOutASCII so the communications between the Arduino and the host uses a similar simple message protocol based on lines of ASCII text.
The benefit of the simple message format is that the output can be read using just the Arduino IDE Serial Monitor for ease of debugging. The code is self-contained, no special libraries are required. The messaging scheme should be fairly easy to extend to handle additional application-specific messages.
Please see the comments in the code for more details on the messaging scheme.
A Python test script is included, for help try the following command: python test_client.py --help