PCI-DAS1602/16 with pacer and external trigger

• From: Michael Borland <michael_borland_at_lynceantech.com>
• Date: Wed, 23 Jul 2003 13:12:50 -0700

I'm trying to use the Measurement Computing PCI-DAS1602/16 with both an 
A/D pacer and an external trigger to start the scan.  My application is 
that I want an external trigger to start the scan, with samples taken 
for all channels in burst mode each time the pacer trigger comes in.

I thought I could do this with
cmd->start_src =        TRIG_EXT;
cmd->scan_begin_src =   TRIG_EXT;
cmd->convert_src =      TRIG_NOW;
cmd->scan_end_src =     TRIG_COUNT;
cmd->scan_end_arg =     n_chan;
cmd->stop_src =         TRIG_COUNT;
cmd->stop_arg =         n_scan;

However, comedi_cmd_test tells me that I have a source conflict.  As I 
understand the board, the start command can only use the external 
trigger, while the scan_begin command can only use the A/D pacer, so 
there should be no conflict.  TRIG_EXT means something different for 
those two commands, or should.

Am I misunderstanding something?  If not, is it sufficient to modify the 
driver for just this board, or is something else involved?

I propose to change cb_pcidas.c at line 1067 from
         if(cmd->start_src == TRIG_EXT &&
                 (cmd->convert_src == TRIG_EXT ||
			cmd->scan_begin_src == TRIG_EXT))
                 err++;
to
         if(cmd->start_src == TRIG_EXT &&
                 cmd->convert_src == TRIG_EXT)
                 err++;

Thanks--Michael

Received on 2003-07-23Z19:12:50