Re: Raspberry Pi for CADCAM CNC? - first task .... realtime RasPi

Running CNC on the RaspberryPi is very experimental, for DIY Linux
kernel experts only, but this might give you a place to begin.

RasPi might run LinuxCNC/EMC2 in non-realtime mode, at least for
testing. Or, non-realtime might just be "good enough" for your
application.

--------

There have been several attempts to get real time running on the RasPi,
including Xenomai on Raspberry Pi

Here are some list excerpts:

http://powet.eu/2012/07/25/raspberry-pi-xenomai/ Xenomai on Raspberry Pi

>
> Ok, I installed it on the Raspberry Pi....
>
> (log in as "jed" password "jed" su to root, as realtime only runs
> in root mode)
>
> ldd hello
> ldd hello2
>
> needs libxenomai.so.0 on the path, so..
> cp -v /usr/xenomai/lib/libxenomai.so.0 /lib
>
>
> now, as root .....
> ./hello works
> ./hello2 works
>
> -------------
>
> problems:
> - its FRENCH linux
> - wrong keyboard, I can't type pipe "|" or quotes
> - startx doesn't work to bring up a graphical UI
>
>
>
>
>> http://powet.eu/2012/07/25/raspberry-pi-xenomai/ Xenomai on Raspberry Pi
>>
>> He says:
>>
>> Xenomai is a real-time development framework cooperating with the
>> Linux kernel, in order to provide a pervasive, interface-agnostic,
>> hard real-time support to user-space applications, seamlessly
>> integrated into the GNU/Linux
>> environment.http://en.wikipedia.org/wiki/Xenomai
>> <http://en.wikipedia.org/wiki/Xenomai>
>>
>> It has slightly different goals than Linux-RTAI, which tries for the
>> absolute minimal latencies. Xenomai attempts to be extensible and
>> have wide compatability. Xenomai used to have a RTAI compatability
>> skin but apparently this is buggy and deprecated. Speedwise RTAI is
>> best followed by xenomai followed by RT_PREEMPT.
>>
>> if you just want to try xenomai here is my latest image (for 8GB HDSC
>> card)
>>
>> wget -c powet.eu/raspberrypi/xenomai.img
>>
>>
>>
>> Username: jed Password: jed
>>
>> SHA-1 bb71b783d3d20edd58287eb1b0bf49bd5d9007de
>>
>>
>> http://www.raspberrypi.org/phpBB3/viewtopic.php?f=41&t=12368
>>
>> I created a patch to get the Raspberry Pi to compile and work with
>> the Xenomai 2.6.1 real-time framework with Linux 3.2.21, which I am
>> sharing here with everybody.
>>
>> After doing some minor testing, it seems to be running fine. Keep in
>> mind that I've never done Linux kernel development before, so it
>> could be that what the code does is wrong is some way, or could be
>> improved. I welcome any suggestions or fixes!
>>
>> Depending on the kernel configuration, the patch will use one of two
>> clock sources for updating the timestamp counter. If power management
>> is enabled, the 1MHz System Timer will be used. If power management
>> is disabled, the ARM Timer, configured to run at 250MHz, will be used
>> instead. Keep in mind that the ARM Timer's clock is derived from the
>> system clock. Since power management can dynamically change the
>> system clock, the ARM Timer is only used if power management is
>> disabled. See section 14 of the BCM2835 ARM Peripherals
>> <http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf>
>> guide for more details.
>>
>>
>>
>

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