Raspberry Pi 4

Yes, but this is still on a RPI4:
"hm2_rpspi: Platform: Raspberry Pi 4 Model B Rev 1.1"

But what does a RPi3 say?

you could put a pullup resistor on the MISO line
If you get 0xFFFFFFFF 0xFFFFFFFF 0xFFFFFFFF
its likely the CE line is not asserted...

That clock rate I see above is likely too fast, just for S&G try 25,000,000. you can go slower yet, but if your cabling is very short and correctly terminated (120 ohms at the rpi4 end of the cable), and mine is only an inch long, it should work. I assume you are switching the target card when trying a different card than a 7i90HD?

Bertho may have better advice, but I am using SPI0 into a 7i90HD on a 2 gig
rpi4b at a write speed of 31,whatever, I think 31,250,000 and a read speed of 25,000,000. I can write at 40 something, but that was not the default I found in the hm2_rpspi.ko source code I have.

But, I am not positive I am using Bertho's latest code as I had to edit the source to slow it read down to at 25 megabits.

Specifying it on the hm2 command line I couldn't make work.

And it doesn't look like it worked above either.

So I am surprised to see 50 megabits above, because that is not whats in the code of the debs you got from my site. If you, gtt38, are running my debs, please elaborate.

Bertho, can you again fwd me the latest driver so I can rebuild the debs? I don't believe I am on the same page as gtt38. Include if it not too unhandy, the sha512 checksum please.

Thanks.

I forgot to add that the code I have does not report its working speeds like the example from gtt38 above shows.

Thanks.

Hi all,
We're currently testing linuxcnc 2.8 on our raspberry pi 4 and an mesa 7c81.
It looks promising but we wanted to determine the real load on the system.
We found a post by PCW which stated that MESA Ethernet cards work optimally when servo-thread.tmax is well below 50% of motion.servo.last-period.
During checking that we found that motion.servo.last-period is always almost equal to [EMCMOT]SERVO_PERIOD rather than the actual number of CPU cycles which should be around 2 million.
This odd since the documentation states that it should be in CPU cycles and our Raspberry Pi is overclocked to 2GHz, as well as our current PC is showing the expected CPU cycles for a 1 millisecond thread.

Is this a known issue on the raspberry pi or did we do something wrong in the configuration of the pi?
Thank you in advance for any help on this issue.

Gene, the latest driver is in the source-tree.

IOW, do a git update or whatever its called. I'll get on it tomorrow.

Looking at the src, I see this:
pi@rpi4:/media/pi/workspace/emc/src/hal/drivers/mesa-hostmot2 $ ls -l hm2_rpspi.c
-rw-r--r-- 1 pi pi 47204 Oct 16 21:53 hm2_rpspi.c

Is that the correct version? Or is it duff?
Thanks bertho

That size seems to be off. You can get the latest version directly from:
raw.githubusercontent.com/LinuxCNC/linux...hostmot2/hm2_rpspi.c

silden wrote:

Hi all,
We're currently testing linuxcnc 2.8 on our raspberry pi 4 and an mesa 7c81.
It looks promising but we wanted to determine the real load on the system.
We found a post by PCW which stated that MESA Ethernet cards work optimally when servo-thread.tmax is well below 50% of motion.servo.last-period.
During checking that we found that motion.servo.last-period is always almost equal to [EMCMOT]SERVO_PERIOD rather than the actual number of CPU cycles which should be around 2 million.
This odd since the documentation states that it should be in CPU cycles and our Raspberry Pi is overclocked to 2GHz, as well as our current PC is showing the expected CPU cycles for a 1 millisecond thread.

Is this a known issue on the raspberry pi or did we do something wrong in the configuration of the pi?
Thank you in advance for any help on this issue.

RPI times are in nanoseconds _not_ CPU clocks (at least they are on the RPI3)

Only 3 bytes diff in size. Swapped it in and debuild is running.