I have a DM648 application where I am using the video port driver (dvsdk version 1.11) to start and stop a raw video display port. I need to control exactly when a frame is output. What I am noticing is the first 2-3 frames after issuing a start command contain all zeros for the data. The process I am using is this:
1.) On startup, initialize the RAW display port and allocate 3 VGA buffers.
2.) Fill all three buffers with data (using 0xFFFF) for this test
3.) Queue all three buffers to the display port
4.) Issue the start command
I see on a scope that the first 3 (or sometimes 2) frames have all zeros for data, and then after that I start to see the frames with 0xFFFF come out.
Does anyone know what causes this behavior? I need to be able to guarantee that when I start the video port that a frame I have filled with data will be put out. I.E. - the first time hsync and vsync start to come out, my data should be on the bus.
Thanks,
Jason
