Raspberry Pi 4

Is it possible to invert the pins with the hal_pi_gpio driver? My controller board needs to take the enable pin low when the machine power is toggled on. I looked at the hal_parport driver since I've used that in the past, but there seems to be code in there for the parport.<p>.pin−<n>−out−invert that isn't in hal_pi_gpio..

Or am I missing something? I'm just getting back into trying to get my mill running after a couple of years in storage, and the PC and controller board died so everything is new and I'm starting from scratch with a rPI (which works ok if I cheat and ground the enable pin separately!)

Hello guys,

I am currently in the middle of a CNC Mill build and I have nearly decided to go with a Raspberry Pi 4 and a Mesa FPGA board to drive the machine. However, even after reading many pages in this thread, I am not sure what the best choice would be in terms of Mesa cards. I was looking at the 7C80 and checking out other ethernet-based cards but I am not sure what the best choices are for the RPi4 in terms of reliability. After watching some videos of people using the RPi4 on their machine (particular this channel www.youtube.com/user/samcoinc/videos ), it seems there are occasional packet drops/issues with his ethernet Mesa card. Is the 7C80 working well for the RPi4? Overall the RPi4 seems to do really well but any advice on avoiding pitfalls with the board and LinuxCNC would be great!

I have been through the same process and decided got with Mesa 7C81+7i85S to interface 3 stepper drives and 3 encoders.
My conversion is now in operation and I'm working on PID loops to use linear encoders on all axis.
You can see some photos and more info in this thread:
forum.linuxcnc.org/27-driver-boards/3889...-pi-4-with-mesa-7c81
The performance of this combination is outstanding as all time critical machine tasks are performed by the FPGA module which is using the super fast SPI interface on the Pi.
My machine is just a basic 3 axis mill, so nothing too demanding, but the the combination of hardware is perfect for the task and has not misbehaved at all, that is not a single failure or miss of anything.
If I was doing another conversion I'd use Pi+7C81+7i85S but I would most likely add another Mesa card to provide a few digital In/Out.

Here is a thread showing how I've added digital In/Out in my current conversion:
forum.linuxcnc.org/27-driver-boards/3882...-as-mesa-anything-io

Thank you Helioz.
Right now I'm just trying to figure out how to power the board and my RPi4. PCW told me that it is possible to power the Mesa card with the Pi instead of the other way around. I'm also a noob so I'm just trying to figure out how to optimize my Pi and to get the Mesa cards working. I got a 7i76 along with my 7c81.

Thorhian wrote: Thank you Helioz.
Right now I'm just trying to figure out how to power the board and my RPi4.

The Pi doesn't have a set of 5V terminals for power, it has the USB-C (or older microUSB) port and the 40pin header.
Powering the 7C81 via the Pi is theoretically possible but not very practical.
Powering the Pi via the USB connector is marginal at the best of times and I certainly wouldn't want to draw even more current though the Pi into the 7C81 and possibly more Mesa IO boards.
The 40pin header is used to connect the 7C81 so isn't really available for power supply.

The 7C81 on the other hand has proper 5V terminals which are capable of supplying power not only to the 7C81 but also to Pi and Mesa IO modules.

The Pi is a power hungry beast and it's peak power draw is between 1-2A, especially when using WiFi. It is common for Pi's to suffer from Voltage drop when powered via the [older] microUSB ports ..... and that's without any additional periphery. Trust me, I've had plenty of low voltage alarms on my other Pi's and I generally try to avoid powering them via the old microUSB as these interfaces are simply not designed to carry the current required by the Pi.

My linuxCNC Pi is supplied via the 7C81 from a 5V 3A power supply and has never suffered "low voltage" issues.

Please, is there some easy way to get linuxcnc-dev installed?
if I remember correctly before it was something like apt-get install linuxcnc-dev