LinuxCNC on Raspberry Pi 5

I don't know that it's chip select.  That's educated speculation.  I believe it's true that the 7c81 requires a SPI connection.  I did some research last night by talking with google's "Bard".  This is what I got.  After the summary, I asked Bard where it found the information. The links to the projects are there.  (Sorry about the cut and paste formatting)

Bard" on RP5 SPI driver
Unfortunately, the Raspberry Pi 5 RP1 driver does not fully support SPI at this time. While basic SPI functionality is available, there are some limitations and missing features:Limitations:

• Limited clock speed: The RP1 driver currently only supports SPI clock speeds up to 10MHz. This is significantly lower than the Raspberry Pi 4 which can reach speeds of 50MHz.
  • Data size limitations: The RP1 driver only supports data transfers of 8 and 16 bits. Larger data sizes like 32-bit are not currently supported.
    • Limited DMA support: DMA transfers are not yet fully implemented for the RP1 driver, which can impact performance.
      
      Missing features:
      • Chip select (CS) support: The RP1 driver lacks proper support for chip select signals, which is crucial for controlling communication between the Raspberry Pi and multiple SPI devices.
        • SPI mode support: Not all SPI modes (e.g., CPOL/CPHA combinations) are currently implemented in the RP1 driver.
          • Interrupt support: Interrupt handling for SPI is not yet available in the RP1 driver.
            
            Current status:The RP1 driver is still under development, and the developers are actively working on adding full SPI support. However, there is no official timeline for when these limitations and missing features will be addressed.
          •  
  • Here are some specific references that I used to gather the information:
    • Official Raspberry Pi SPI documentation: pinout.xyz/pinout/spi
    • Raspberry Pi forum thread on SPI support:
    • ​​​​​​​ www.abelectronics.co.uk/kb/article/2/spi...ux-on-a-raspberry-pi
    • Technical blog post on Raspberry Pi 5 features: www.tomshardware.com/reviews/raspberry-pi-5
    • RP1 driver code repository on GitHub: github.com/jncronin/rpi-boot
      RP1 driver issue tracker on GitHub: github.com/raspberrypi/firmware/issues

There's no need to "believe" that the 7c81 uses the SPI it does, unless you change the firmware for EPP and cook up a custom connector & use the hm2_7i90 driver to talk to the 7c81 over the parallel port.

github.com/jncronin/rpi-boot The last commit was in Feb 16 of 2022 I don't get why this is relevant.

www.abelectronics.co.uk/kb/article/2/spi...ux-on-a-raspberry-pi is well out of date

www.tomshardware.com/reviews/raspberry-pi-5 is just a run of the mill blurb on the RPi5, there is no mention of SPI.

github.com/raspberrypi/firmware/issues Has no issues related to the RPi5 & SPI

The resources you listed aren't really that helpful. The fact that the RP1 documentation isn't mentioned is absolutely astonishing. Next time could you you actually look through any resources you are given and sort out what is relevant and what is not. A few predate the release of the RPi5.

And as far as my research has led me, there is no "RP1" driver (although I havent played with the latest kernel), the SPI side is covered by the spi_bcm2835 driver. The hm2_spi driver uses this.

Another thing that is an issue in the hm2_rpspi driver is where it gathers the information for the clock, it's in a different location.

Actually I'm going to blow out of this part of the discussion. Good luck & all the best.

If you really want to get the attention of the devs your best course of action would to be raise an issue on github or via the emc mailing lists, the relevant information for those resources can be found on the Linuxcnc homepage.

thadwald wrote:

This image can be downloaded from here
drive.google.com/file/d/16kKamxMKPdYAeJp...KLf/view?usp=sharing
At first glance everything seems to work regularly and the lowest value that did not show the "Unexpected realtime delay" message was
latency-test 12000
Trying your image now. ... what username and pw does it take?

user: pi
pwd: raspberry

Thanks for the feedback. I'm just feeling my way into this. I don't have a magic solution. I think we can agree that the new image still doesn't talk to the 7c81. I will start to follow the emc mailing lists.

Bought my first Pi yesterday from Core electronics in Australia. Considering the fact i live in New Zealand, the UNDER 24 hours from order to delivery was just astonishing- cant recommend that company highly enough- and nobody in NZ had the 8gig Pi5, so it was even more unexpected that things might go this smoothly

 

I would like some help installing linuxcnc for raspberry pi 5. How to configure the hal file to access gpio in version 5. Does anyone have a working model hal file for the raspberry pi5 and could share it with me?