Gradus M1 Pro - Information

I just built a MiniMill and equipped it with the Panucatt Gradus M1 Pro controller (and Bigfoot BSD109A drivers). The controller (supposedly) comes with Grbl 0.9 pre-installed.

Well I couldn't get grbl-panel or chilipeppr to give me any sort of movement or feedback at all from the board. It would connect, but there was no 2-way communication. The documentation online for this board is very poor. It consists of a few specifications and a 1-page basic wiring diagram.

Long story short, I finally got it working. I feel like this board needs to be better documented somewhere ... so this will be one place, at least.

See the currently available specs for this board here: Gradus M1 PRO GRBL CNC Controller

Additional info:

• The board can NOT be powered from USB alone!
• Processor: Atmel Mega328P (5V, 16 MHz for flashing)
• USB Isolator: ADUM4160BRWZ
• Com Port Device (on mine): DA01NQCJ
• Arduino Target: Arduino Pro or Pro Mini
• Arduino Programmer: AVRISP mkII
• M1 Pro does not have digital pots (for setting VRef on drivers). If you are using Bigfoots, you must add the VRef jumper, and manually set VRef with the onboard pot. (Bigfoots seem to be sensitive to VRef. Mine works well between 0.70-0.75V. Much higher disables the driver.)

After some frustrating trial and error to discover the info above, I have successfully flashed my board with grbl 1.1 - And grbl-panel is now able to communicate with it! (So I conclude that grbl 0.9 was not pre-loaded on the board I got.)

If you want to check or flash your M1 Pro before you mount it, you can power it with 3-cell lipo or something.

Anyway, I will get this board installed back to my MiniMill and perform further configuration and testing. I will update this resource as I learn more that is specific to the Gradus M1 Pro.

1-10-2018: For step-by-step instructions on wiring and flashing the M1 Pro (including wiring diagrams for the M1 and Bigfoot drivers), see levitations tutorial resource: https://openbuilds.com/projectresou...foot-tutorial-for-absolute-beginners-1-0.288/

If you've learned something about it that was difficult to find or figure out, post it in the discussion section, and I can add it on the main page here.

Cheers,
Scotty