EMC2 running on Raspberry Pi?

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13 years 1 month ago #39183 by andypugh

mungkie wrote: Which git branch should I grab?

Probably unified-build-candidate-3

What is happening with the universal RTOS thing?

That's what ubc3 is. It ought to be as simple as ./configure --with-platform=raspberry. I can't guarantee that it is.

How should I post my dma based stepgen driver?

What format is it in? Is it a standalone C-file that could live in src/hal/drivers? Some makefile-fu might be needed in order to have it only compile on RPi.

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13 years 4 weeks ago #39480 by mungkie

andypugh wrote:

How should I post my dma based stepgen driver?

What format is it in? Is it a standalone C-file that could live in src/hal/drivers? Some makefile-fu might be needed in order to have it only compile on RPi.


The driver I found on my old dev vm is almost identical to the code in this linuxcnc.org/index.php/english/forum/18-...y-pi?start=140#32939 post.

There were only very minor changes to the output code but I added a few functions to start experimenting with dma based gpio reads (not even tested or debugged just outline code).

I am sort of going back to getting a decent RT kernel compiled(which is not going well), as I think that needs to be fixed before I start looking at the driver code.

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13 years 4 weeks ago #39481 by mungkie
As said above I am trying to get a decent RT kernel compiled, I started again on the rpi linuxcnc as I has hoped the kernel infrastructure would be more mature work better and be simpler to patch with xenomai and RT_PREEMPT for the 3.6 or 3.8 kernels.

Unfortunatley this does not seem the case, I have done some tests with 3.8 patched with xenomai and RT_PREEMPT and they seem to have appaling RT performance. I then thought maybe I should checkout kinsas git repo of rpi xenomai patched kernel and that would not even boot to a login prompt.

The compiled kernel cyclictest results for 3.8 xen/RTPREMPT were and order of magnitude worse that the cyclictest results from the 3.2.27 RT_PREEMPT on the released image. I think the fiq code may have caused this?

I am not really a kernel hacker so I don't know enough to be productive in trying to fix anything.

So I am wondering where to head next, I will probably leave things for a while to see what happens, but maybe will go back to the 3.2.27 branch that is on the image I released and look at how to get the VC vchiq interface working.

The 3.2.27 kernel on the image I released before had quite a few problems such as inability to run VC code (problems with the firmware interface?) and the networking caused problems sometimes(that is why networking was disabled when linuxcnc is run). I Was hoping leaving things to mature would make it possible to come back and start with a newer more stable system, but I probably need to actually hack the kernel myself which is not something I am confident with (just understanding the codebase would take many more hours than I have available in free time).

I will keep looking at things, as something may and probably will improve soon.

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13 years 4 weeks ago #39482 by andypugh

mungkie wrote: As said above I am trying to get a decent RT kernel compiled,.


Have you seen: static.mah.priv.at/public/html/common/UnifiedBuild.html
and specifically section 7?

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12 years 11 months ago #41285 by ADBensi
Hello to all,

  I'm new to the forum, I'm downloading the RPI-lcnc.img image and plan to mount a PICnc Jr Board to participate with you.

  I have a Raspberry controlling 4 stepper motors using ethernet (Delphi program and drivers direct on Raspberry), and has since I turned into an enthusiastic with CNCs.

  When I understand how this work works I would port it to Cubieboard (DDR3 1GB, 1GHz, 4GB).

This would motivate me to learn about Realtime Kernel and would be mode to exchange experiences with the group.

Best Regards

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12 years 10 months ago #41286 by andypugh

ADBensi wrote: I'm new to the forum, I'm downloading the RPI-lcnc.img image and plan to mount a PICnc Jr Board to participate with you.

Just by way of a warning, when I tried using the RPi step generator of real hardware I found that the pulse train wasn't very regular, and it didn't work very well.
I think that more development is needed.
LinuxCNC is known to work well on the Beagle Bone Black, and I am hoping to see if I can get it working on the Udoo board (which is an ARM PC, with an on-board Arduino.

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