- From: Bernd Porr <BerndPorr_at_f2s.com>
- Date: Mon, 04 Oct 2004 14:56:20 +0100
Hi!
I do this usually with two comedi commands. One to aquire the data and
one which sends out the stuff. Under 2.6 with the preemptive option I
get 1kHz realtime I/O with just a "while (1)"-loop. My colleague Tao is
controlling a walking robot in that way. I've copied the mail to him.
/Bernd
www: http://www.berndporr.me.uk/
http://www.linux-usb-daq.co.uk/
Mobile: +44 (0)7840 340069
Work: +44 (0)141 330 5237
University of Glasgow
Department of Electronics & Electrical Engineering
Room 519, Rankine Building, Oakfield Avenue,
Glasgow, G12 8LT
Nils Juergens wrote:
> On Fri, 01.10.04, Michael Thomas <Michael.Thomas_at_dynetics.com> wrote:
>
>
>>trigger? That still wouldn't help my user code stay synced up. It just
>>seems there should be a better way.
>
>
> If it's a real time problem (it smells like one :-)) ) you need a real time
> system, e.g. RTAI.
>
> It might work like this:
>
> * create an RTAI task
> * make task periodic
>
> in the task (via kcomedilib)
> * read samples (comedi_do_insn())
> * do stuff (calculations etc.)
> * write samples (comedi_do_insn())
>
> I think it's also possible to combine this method and comedi_command (for
> increased performance and decreased jitter in the sampling periode).
>
> hth,
> Nils
>
Received on 2004-10-04Z12:56:20