Re: Software triggering a PCDig

["M.Stein" <matthias@gom.com>]

On Fri, 31 Mar 2000, Will Lockhart wrote:

> M.Stein writes:
>  > But if the camera is only readout, when the next frame (line) is being
>  > exposured, than you can drive the camera only in a continuous mode,
>  > because you need more than one frame (line) to get a valid image.
>  > Am I right?
> 
> Basically yes.
> 
>  > Do you get a valid image, when set to EXSYNC_FREE_RUNNING? Perhaps you
>  > have to outwit driver a little bit (the driver calculates the exsync
>  > cycle time by adding EXSYNC_PERIOD_TIME and *MIDPOINT_DELAY - the naming
>  > is wrong, but config file compatibility is all), setting the 
>  > *MIDPOINT_DELAY to a small value, but not to zero.
> 
> Yes, I get a valid image when set to EXSYNC_FREE_RUNNING. Changing the 
> values of *MIDPOINT_DELAY doesn't seem to make any difference (it
> might be changing the exposure time slightly, but I can' tell if it
> is).
> 
> The PCDIG hardware reference says:
> 
> External Trigger Acquisition

Will, I have misunderstood you! The external trigger acquistion of the
board is a completely different thing to what we do. We trigger the
EXSYNC subsystem of the board.
You want to let the camera run free and want to take one of these images
to a defined point of time (per software trigger or hardware trigger).

So set the EXSYNC_MODE to free run and the camera makes it's images
continuous. Then start the test_itifg WITH the -t option and start
swtrig_itifg -k (the swtrig_itifg program does both - it can trigger
the board and the exsync subsystem).

Unfortunately there is no config file option or ioctl to change the
trigger source yet, so you have to edit itifgIoctl.c line 1101:

hardware: (pcd_set_stmode, PCD_TMODE_HWT0_SET) (default)
software: (pcd_set_stmode, PCD_TMODE_SWT0)

Please remark - The board trigger mode is NOT supported in 0.7.0!

 
						matthias


 
> Line Scan: After the trigger occurs, the next selected edge of LEN
> begins the acquisition. The vertical active register defines the
> number of lines acquired, to create a frame.
> 
> I assumed that external trigger and software trigger would work the
> same way, but for software trigger it says:
> 
> In software trigger mode the EXSYNC pulse is asserted whenever the
> host writes to the Software Trigger register.
> 
> So it looks as if I can't use a software trigger to acquire a whole
> frame (which is OK, because I don't want to - I want to use an
> external trigger, but I thought this would be a good way to test
> triggering in general).
> 
>  > 					matthias
> 
> Will
>