Re: Using a trigger for multiple devices

From: Bernd Porr <BerndPorr_at_f2s.com> · Date: Fri, 24 Sep 2004 10:10:28 +0100

Jan,

it depends on the reaction time. You can poll the digital port by the 
standard dio commands and then start the asyncrounous acquistion.

However, some drivers support that feature internally with the flag 
TRIG_EXT. The argument is then the channel number.

It's on my todo list for our board. It's not very difficult. I thought 
about that in the context of an oscilloscope program. Like in an 
analogue oscilloscope you want to set a trigger which starts the 
acquisition.

/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

Jan Klostermann wrote:
> Hello!
> 
> I am wondering if the comedi framework supports software triggering
> across several devices. Even if it might not be implemented in any
> driver yet, is there a functionality implemented in the framework that
> allows to use a trigger event created by one hardware (e.g. a digital
> input, possibly of the parallel port) to start/stop/whatoever the
> acquisition of another device (e.g. an analog-DAQ via comedi_command())?
> 
> It would be really cool having something like this...
> 
> Jan Klostermann
> 
> 
> _______________________________________________
> comedi mailing list
> comedi_at_comedi.org
> https://cvs.comedi.org/cgi-bin/mailman/listinfo/comedi