Is there a specific .nc config I'm missing here. Flatcam is doing exactly as i need for pcbs but cannot get cnc control to run. Constantly getting Error 20
Haven't used FlatCAM in a while, does it allow you to pick a gcode flavour/post processor/firmware type anywhere in its settings (Make sure it exports Grbl compatible gcode) - I don't recall it needing anything special Error 20 = Unsupported or invalid g-code command found in block. So something in your GCODE is not Grbl compatible entirely Or post the file for review, perhaps invalid gcode in your Prepend/Append blocks?
You are correct i can change gcode flavour to GRBL_11_NO_M6. this seems to have resolved the issue. Just have to manually start the spindle but otherwise fine.
That's what the Prepend/Append blocks are for, add your M3Sxxx where xxx = RPM (or 1000 if its a IoT+Router setup) commands for on and M5 for off, G4 Pxxx where xxx = seconds to delay after powering up to give spindle time to come up to speed etc If you have a moment, do grab screenshots of the process to pick GRBL_11_NO_M6, we don't mind adding it to the docs to helps the next person