This guide documents how I set up a Raspberry Pi 4 to run LinuxCNC 2.8 along with a Mesa 7i76e FPGA board. The Pi communicates with the 7i76e over Ethernet.
This is the process that worked for me in December 2020. These steps may become outdated since LinuxCNC and Raspbian are under constant development.
sudo nano /etc/dhcpcd.conf
sudo apt-get install xrdp
mesaflash --device 7i76e --addr 10.10.10.10 --readhmid to check current board configuration.
mesaflash --device 7i76e --addr 10.10.10.10 --write /home/pi/Downloads/7i76e/configs/hostmot2/7i76e_7i76x1D.bit
When first testing steppers for motion, ensure all joints are homed prior to attempting to move the steppers, otherwise the display will show motion but the motors won’t move.
If an axis moves in the wrong direction, re-run Pncconf and check off the option for Invert Direction.
Use 'dhcpcd.conf' rather than 'interfaces' for setting up network connections for linux versions later than Wheezy (Jessie, Stretch, etc.).
Support software and manual for the 7i76e are found at http://www.mesanet.com/ under the product page for Anything IO FPGA Cards, the scroll down to 7i76e.
Note: I read that Raspberry Pi hardware with 8GB RAM had known compatibility issues with LinuxCNC at the time I wrote this. I’m using a 4GB version so it wasn’t an issue and I didn’t read any further into the details. If you have an 8GB Pi and run into any problems you may want to research this.