You can use a g-shield (or cnc-shield) without the stepper drivers for this. The only signals you’ll need for the stepper drivers are STEP and DIRECTION.
I’ve mentioned in previous posts, that I run my X-Carve under Linuxcnc with a Gecko G540 controller. It works well and I’ve been successfully creating gcode using (mostly) CamBam . However, I can’t access all the goodies that Easel provides unless I run grbl. This thread will document the process of getting grbl to drive the Gecko G540 controller.
First step was to get a couple of Ardunio Unos (if there are two Uno, does that make it a Due?