Now speed and rotation controlled from g-code.

Now speed and rotation controlled from g-code. I am using a second serial port for the VFD control with an Arduino Mega runing Marlin firmware. You can see the M3/M4/M5 commands in the center window.
https://vimeo.com/109340551

Marlin does not support M3-M5 commands but grbl does. The problem with this matter is that each VFD is different so it won’t work with a different hardware. Secondly, grbl is kind of tight code-wise so this might not fit because, thirdly, an additional serial port is needed (which Arduino UNO lacks of, and the software serial library will require even more code).

So I am afraid it may be a tough sale for grbl maintainers. Things change, however, if you use grbl on an Arduino Mega with plenty of free space for additional code and three additional serial ports.

Anyway, you can use my code freely http://pastie.org/9660347

+Peter van der Walt No, I am using Marlin on a single Arduino Mega for controlling a CNC. Marlin is designed for 3D printing but it works for me and it offers 40Khz pulse rate. I am using Serial2 with a RS485 driver for controlling the VFD and Serial0 for USB comms.

I can see one Arduino UNO board that shows on the top right corner of the video, but that one is just lying on my table and not connected in this case.

+Peter van der Walt anyway, here you have the grbl isssue: https://github.com/grbl/grbl/issues/516

+Peter van der Walt and there it goes https://github.com/grbl/grbl/issues/516#event-180911594

Miguel. Do you think using a beagle bone + cramps is a good idea for a CNC

@Janardhan_Raju Certainly, but drivers may fall short of current though.

Which drivers r u using on your current CNC

Does marlin support all the grbl g codes

@Janardhan_Raju No, it does not, but being open source it means you can add commands as you need them

@Janardhan_Raju Sorry, I missed this question of yours: I am using M542 drivers http://www.leadshine.com/UploadFile/Down/M542d.pdf