David , the GRBL version is 0.9j The source is from the Arduino GRBL library and I did not specify any compiler options in the Arduino IDE. the board is from Amazon... https://www.amazon.com/gp/product/B06XSC52SL/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1 No versioning or date on the board. The UNO that came with the board had a dead D8 pin, so I couldn't use it. The one I used instead is ... https://www.amazon.com/gp/product/B0168B39N4/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 I have bought a few of these boards and had good luck with them. I have a lagit UNO but didn't want to use it until I know everything else is good. (if at all) I could do without PWM if needed, but not sure how to go about "...but compile options can change it back "