- From: Bernd Porr <BerndPorr_at_f2s.com>
- Date: Sun, 02 Oct 2005 15:52:54 +0100
Hi Per,
the ao_waveform has a timer-argument on its own. You can have it running at
denominations of 1kHz. I think ao_waveform runs by default with the max rate
(here 1kHz). The userland code has then to supply data sufficiently often so
that the comedi buffer never runs out of data.
The sampling rate of the counter of 500Hz means that you can send in frequencies
of max 250Hz so that no flanks are missed. Realistically its more 100Hz probably.
To reset the counter issue ./out -s 3 -c 0 0 to reset the first counter.
/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
Per Arlock wrote:
> Hi Bernd,
>
> Thank you very much for the immediate answer yesterday! I got it the last time when you answered that they are counters and not timers. What I did not understand was that they were not running without an external clock!
> How is then the ao_waveform running? Simply as fast as possible?
> In the docs on usb it is said that the sampling rate of the counter is 500 Hz. What would that mean? Can I run a square-wave generator at for example 100 kHz and get my clock from there?
> Writing a program under Kylix which polls the counter will not be very problematic!
> Do I reset and do up/down like ./out -s 3
>
> I would be very grateful if I could get some answers to these question!
> Best regards!
> per
>
Received on 2005-10-02Z13:52:54