Re: NI 6034E, EXT_TRIG

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On Thursday 29 May 2003 02:15 pm, Martin Merz wrote:
> When i set TRIG_WAKE_EOS the read() - Function comes always back with
> "read: broken pipe". So i compiled the driver with  "#undef PCIDMA" (in
> ni_pcimio.c), i read this in the Mailinglist. This time it seems better.

I put some fixes into cvs to try and get TRIG_WAKE_EOS to work with PCIDMA 
enabled.  Would you test that?

>
> How many scans .... good question. When i set this (Example 1):
> 	cmd->scan_end_src =	TRIG_COUNT;
> 	cmd->scan_end_arg =	2;
> 	cmd->stop_src =		TRIG_COUNT;
> 	cmd->stop_arg =		1;
> i got more than one scans or converts !? ... it's endles. After each
> convert the read comes back. I thought after each scan the read() comes
> with the analog values and after that with an ret Value 0 !?

It's a hardware limitation, you can't ask for less than 2 scans.  The 
driver catches it during the command test now.

>
> My questions:
> 1. Is this the right way to read from the analog channels and the dio's

Well, there may be a significant delay between the analog scan completing 
and you reading the dio lines.  Ideally, you would use dio hardware that 
supported external triggering.  The driver support in comedi for dio 
commands is not very extensive yet however.

- -- 
Frank

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Received on 2003-05-29Z21:43:57