LinuxCNC on Raspberry Pi 4

Deadtoxxic wrote:

Hi All,

I also faced with this when iam using "LinuxCNC 2.8.1  Raspberry Pi OS based on Debian 10 Buster", but on 4GB version of RPI4.
I tried with two different SD car, with one USB flash drive, and with external SSD, but same result unfortunatelly.
Apart from everything, somebody have any clue what the problem?

Following elovalvo:
1. I tried to install a PREEMPT_RT kernel, but i am stuck with that.
2. Buildbot: When i want to reach this page, i recieved this message: "this site can’t be reached"

How should i proceed?
Thank you in advance!
 

From the photo you uploaded it seems that there is a problem at startup because the SD is not recognized and tries to boot from USB.

My suggestion is to download the full image (Raspbian Buster 64 + LinuxCNC 2.8.2) from this link

drive.google.com/file/d/1sdFvmJx439lZQsq...jQE/view?usp=sharing

and use the Raspberry Pi Imager

www.raspberrypi.com/software/

to write to an SD, avoiding booting from external USB.

Is there any documentation about configuring the GPIO's? My X86 system died, and I am trying to switch to my RPi4B (8GB).
I managed on the RPi to install LinuxCNC 2.8.2 on an SSD. However the documentation in that kit is not related to GPIO's it seems. Also the latest version of the LinuxCNC_documentation.pdf does not mention them.

I installed the utility rpi-gpio, but have no idea what the generated output means. Are there any GPIO configuration examples?

Thanks,
Robert
 

in this link you can find an example of configuration:

forum.linuxcnc.org/9-installing-linuxcnc...-io-pins-only#203365

LinuxCNC has a driver for the Pi GPIO, but it is barely documented (and as it only builds at all when the target is the Pi it doesn't show up in the lists)

There is an example HAL file, and that's your lot. Sadly.

github.com/LinuxCNC/linuxcnc/blob/master...hal_pi_gpio_demo.hal

Hy Gents.

Sorry for my late reply... Thank you for your help, Iam on the way to get a system running, but i still have a problem.

1. RPI4 4GB version booted from external SSD trough 3.0USB port. Using this OS: "2021-08-01_2021-05-07-realtimepi-buster-armhf-lite-0.6.0" from unofficialpi.
2. I installed the XFCE desktop with ( xserver-xorg xfce4 xfce4-goodies) .
3. Installing Linuxcnc Uspace from buildbot "linuxcnc-uspace_2.9.0~pre0.6129.g907754aa9_armhf.deb" 
4. Then I get this latency  

I tried it with SD card ( speed class 10) but the result is worse. Anyway i will use it with 7I76e, so achieve software step generation is not my target.
But i feel something is not working properly. Do you have any idea?
Anywhere in the forum i can see good latency results with RPI4 with realtime kernel combined with Uspace.

Thank You!

Maybe try the SD card image here?
forum.linuxcnc.org/9-installing-linuxcnc...cnc?start=130#238020