Re: Multiplexing on USBDuxFast

From: Harish Ganapathy <drgharish_at_gmail.com> · Date: Mon, 20 Nov 2006 13:35:05 +0530

Thanks, I tried to use 6 channel at 3MHz and got a bad address error.
The  driver seems to have cases for 1, 2, 3 and 16 channel only. Is
there a driver that can handle channels 0 to 5 or can I find the
explanation of the dux_commands structure to attempt it on my own? If I
use all 16 channels, I get ~180 khz/channel which is much less than the
500 khz I80 khz can get if I acquire only channel 0 to 5.

Also, Where can I get the GPL version of the firmware source code (the
usbduxfast site says this is available) to attempt to see if single
channel acquisition can be extended to any channel, not just Channel 0?

Thanks
Harish Ganapathy, PhD
Technical Director
IQC Data Acqusition Systems
Chennai, India
email: drgharish_at_gmail.com

On Sat, 2006-11-18 at 11:12 +0000, Bernd Porr wrote:
> Hi,
> sorry. I haven't implemented that. If you just want one channel it's 
> just now always channel 0. But of course this could be added to the 
> firmware.
> 
> Here's a new version I'm just now testing which uses the external 
> trigger signal and a modified cmd.c for external triggger (from the demo 
> directory).
> 
> /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
> 
> 
> Harish Ganapathy wrote:
> > Hi,
> > 	I am trying to use a USBDuxfast in an application which has 6 channels
> > of output. I wanted to know if it is possible to scan one channel at a
> > time on trigger for about 256 samples at 30Mhz. It works for channel 0,
> > but I cannot get it to work for other channels. In other words, if I
> > wanted only to sample say Channel 4 at 30 MHz, is it possible? 
> > 
> > Thanks
> > Harish Ganapathy, PhD
> > Technical Director
> > IQC Data Acqusition Systems
> > Chennai, India
> > email: drgharish_at_gmail.com
> > 
> > 
> > _______________________________________________
> > comedi mailing list
> > comedi_at_comedi.org
> > https://cvs.comedi.org/cgi-bin/mailman/listinfo/comedi
> > 