PCIe-1433: pulse train to CC1, in C++?

Question

I'm sure this should be a simple question and there's a lot of good information from previous threads but I can't quite put it together.
I have a PCIe-1433 and a Point Grey Gazelle; everything works okay, and in the Camera File Generator, I can put the camera into bulb-shutter mode and correctly control the exposure. So, through the camera file, control of CC1 works well.
But now I want to programmaticaly generate a simple pulse train, to CC1 of this camera. CC1 is already set as "external" line 0 in MAX. I believe I am correctly putting the camera into external trigger mode because the frame rate drops to 0 (or the timeout rate). The commands are a bit confusing to me; currently I am using
imgPulseCreate2(PULSE_TIMEBASE_50MHZ, 50000, 50000, IMG_SIGNAL_STATUS, IMG_IMMEDIATE,
IMG_TRIG_POLAR_ACTIVEH,IMG_SIGNAL_EXTERNAL, 0, IMG_PULSE_POLAR_ACTIVEH,
 PULSE_MODE_TRAIN, &pulseId);
imgPulseStart(pulseId, sessionId);
No errors reported (after some trial and error), but I don't believe it's creating a pulse. I need to do this programmatically because I will need to vary the pulse rate to something the camera can support for different ROI's, although if there is a combination of using the camera file and code I would be happy to use that.
Any help would be greatly appreciated!

Answer 1

GREAT! Thank you Eric, starting with your tip and then some more trial and error, I've got it going now. A few things:
* The attribute I was trying to modify actually only involved a pulse width, but it still wanted me to stop the acquisition.
* The solution ended up being to code the camera mode (set by serial commands to first set the trigger source to CC1, then set the trigger mode to single) in the camera file.
For some reason that I'll figure out one day, sending these same codes with serial write just did not work at all. Even if I told the camera file not to send any serial codes at all, ever, sending the same two commands myself didn't seem to work (even though I got acknowledgement from the camera). I'd like to solve this because I believe that calling AcquisitionStart resends these codes (for example, when I set up for a sequence acquisition) but this is redundant and slows things down.
* So now I tell the camera file to send "trsrc line1\r" and "trm single\r", but with no pulse output. Then in the code, I use the commands below to set the pulse.
imgPulseCreate(PULSE_TIMEBASE_50MHZ, 70000, 70000, IMG_IMMEDIATE,
IMG_TRIG_POLAR_ACTIVEH,IMG_EXT_TRIG0, IMG_PULSE_POLAR_ACTIVEH,
PULSE_MODE_TRAIN, &pulseId);
imgPulseStart(pulseId, sessionId);
then, to change the exposure time:
imgPulseUpdate(pulseId, sessionId, delay, width);