Do the register and attributes do the same work in a fireware camera?

[xu27]

Hi,

I am programing a AVT Guppy Pro F031b 1394b camera with IMAQdx.

I can use property nodes to turn on the trigger modes as well as use the writing register to turn on trigger mode.  But it seem this two method give me different result.

Intially, trigger is off for both of the following test.

1st, I set trigger mode = mode 0 by property modes. And then I get time out error message since I didn't input trigger.

2nd. I write the trigger register to set as triggered 1 shot( trigger mode0).  I also didn't send trigger. But I get a different error message telling me that no image file found.

I am wodering are these two methods doing the same thing?   If I write register, shall I see a change of the attributes value? 

[fblerg]

Hi Xu,

There 2 methods should be equivalent. The register write function might be simply writing to the camera's internal register, and not waiting for a response from the camera, while the property node could be listening for a response. I would suggest the property node method. You might also want to check on the register values that you are sending. The IMAQdx Write Register function  byte swaps the data for big endian alignment before transferring the data.

[BlueCheese]

You have to be careful interacting directly with registers that are also controlled by IMAQdx's property nodes and other features. I think the Firewire driver might do some optimizations where it only flushes all the camera settings (including trigger settings) to the camera when you start the acquisition, since the DCAM model is pretty well defined and registers have very little interaction with each other. If you end up touching registers that IMAQdx is also touching, you may need to play games with ordering to make sure it works how you like.

[xu27]

Thank you very much!  I found these two method can do the same work. But the way to program is a little bit different. 1. attribute:  when I write an attribute,  this new attribute will hold until I rewrite or when I end the session.  The attribute can only be writen when the camera is idle. 2. register:  It seems the register will be effect imediately but when I config the camera( like use grab function from IMAQdx), the trigger will disappear.  I am not 100% sure about the resigter way, but I think it's worthwell the share. 

[xu27]

Thank you very much, fblerg and BlueCheese!  Your comments are very helpful.