@world101 I couldn't get it to work with the Universal G code sender. It was like it could tell it was there, but it didn't seem to communicate. I think there's a lot to do with it all being ESP32 based or that you're going through a computer through the esp32 to the grbl module...I'm not sure. there is a I've not gotten any further along with it. I pretty much put it to the side and had hoped to come back to it. I think you could read line by line from a file on the SD card and write it to the GRBL module. So on my Shapeoko cnc router I can use the command $$ to see the parameters and settings and change many variables to setup a machine as you need it set. I do not see how you can do that with this device. Maybe in the arduino environment you can you the serial monitor. I was really disappointed that there is no documentation for this and I have found very little online.
I did find this, but I just didn't have the time to go down this rabbit hole. link text