Re: External Trigger

From: Frank Mori Hess <fmhess_at_users.sourceforge.net> · Date: Sat, 5 Jun 2004 12:56:02 -0400

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I thinks it's fixed in cvs now.  You should probably do

cmd->start_src = TRIG_EXT;
cmd->start_arg = 2 | CR_INVERT | CR_EDGE;

assuming you want the aquisition to start on a falling edge, as opposed to 
doing a scan on each falling edge (in which case you would be using 
scan_begin_src and _arg).

On Monday 31 May 2004 06:57 am, David wrote:
> Hi all again.
>
> We are still working with external trigger and it doesn't
> work for falling edge. Frank told us about using CR_INVERT
> but it doesn't work. We are not sure if we are doing it in
> right way.
>
> for example por PFI2 falling EDGE we are using
>
> cmd->start_src = TRIG_NOW
> cmd->start_arg = 2 | CR_INVERT;
>
> is that correct? should it work?
>
> We'have been studing ni_mio_common.c and in the
> ni_ai_cmdtest function (step 3). If start_arg is over nine
> it asign the value of 9 to the cmd->start_arg, so when later
> in function ni_ai_cmd do win_out (AI_START2_Select(0)|
> AI_START1_Sync | AI_START1_Edge |AI_SART1_Select (chan+1),
> AI_Trigger_Select_Register) the value written to the
> AI_Trigger_Select_Register is always 0x006A and the most
> significant bit must be 1 to be falling edge. Besides the
> PFIX selected is always nine.
>
> anyone knows anything about that?
> -- Daniel Machón [damachon_at_eresmas.net] --
>
>
> _______________________________________________
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- -- 
Frank

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