Remora - Rpi Software Stepping Using External Microcontroller via SPI

Hello,
I am following the Remora documentation for Linuxcnc Installation on a Pi 3B+, but I am have difficulties such as the frozen rainbow screen upon reboot.
I have tried a couple of class 10 sd cards (Transcend 8GB and Scandisk Ultra 32GB) and the Pi is powered by the official white AC power supply (low power often cited in rainbow screen problems).  This procedure is the same as linuxcnc.org/docs/html/getting-started/getting-linuxcnc.html .

Is it appropriate to use a Pi 3B+ with the linux-image-4.19.71-rt24-v7l+ Realtime kernel?
         or just forget it and buy a Pi 4?
Is the Debian Bullseye 2022-09-22 OS appropriate for the starting point?
Is a 32GB sd card large enough?
Is there an alternative procedure to create the sd image?
 

TimGow wrote:

Hello,
I am following the Remora documentation for Linuxcnc Installation on a Pi 3B+, but I am have difficulties such as the frozen rainbow screen upon reboot.
I have tried a couple of class 10 sd cards (Transcend 8GB and Scandisk Ultra 32GB) and the Pi is powered by the official white AC power supply (low power often cited in rainbow screen problems).  This procedure is the same as linuxcnc.org/docs/html/getting-started/getting-linuxcnc.html .
 

You can't use that procedure on 3B+ because the image
www.linuxcnc.org/iso/linuxcnc-2.8.1-pi4.zip
is for Pi 4

Is it appropriate to use a Pi 3B+ with the linux-image-4.19.71-rt24-v7l+ Realtime kernel?
         or just forget it and buy a Pi 4?
 

I think you can use 3B+ but there are more updated realtime kernels

Is the Debian Bullseye 2022-09-22 OS appropriate for the starting point?
 

No, if you want to use LinuxCNC version 2.8.4. This version runs with Buster

Is a 32GB sd card large enough?

yes, 8 GB is enough to work even if 32 is obviously better

Is there an alternative procedure to create the sd image?
 

yes, for example this
linuxcnc.org/docs/html/getting-started/g...lling_on_raspbian_10

which also works on Pi 3B+ ( v71+ for armhf)

Anyway I'm preparing an image with buster and LinuxCNC 2.8.4 32 bit for 3B+, Pi 4 and Pi400[/quote]

elovalvo wrote:

Anyway I'm preparing an image with buster and LinuxCNC 2.8.4 32 bit for 3B+, Pi 4 and Pi400

The image can be downloaded from this link

forum.linuxcnc.org/9-installing-linuxcnc...erry-pi-3b-pi#260915

elovalvo,
Thank you very much for your generous reply to my beginner LCNC questions and your time in providing the image.

I'm away from my CNC due to work but I will use your guidance asap.

Kind regards,
Tim

Thanks for the replay.
Do you have any idea why the hardware PWM mode does not work (no response at PIN). As software PWM the PIN works. I have already tested some but everywhere the same software ok but hardware no reaction. I need 1kHz or better even more, which the software PWM does not provide. Or is a pin from Rasperry also possible to use?

    {
    "Thread": "Servo",
    "Type": "PWM",
        "Comment":             "PWM Laser",
        "Hardware PWM":     "True",
        "SP":                    0,
        "PWM Pin":             "PD_15"
    }

Only certain pins can do hardware PWM.
What board and software branch are you using?