Honored Contributor
Honored Contributorhi,
regarding the Avalon-ST spec (see attached file), I'w placed a custom module infront of the VIP mixer module. The purpose of the custom module is to provide alpha values to the alpha blending mixer's alpha input port (only for the 640x480 stream). The custom module receives the 800x600 stream from the VIP Frame Reader module and this steam is shifted "as is" straight through the custom module. The same goes for the 640x480 stream, which is received from an VIP Frame Buffer. Since the 800x600 stream is the background layer, it's alpha values are ignored, and all I'm actually doing is that I'm using row and column counter and providing alpha values for the 640x480 stream. Also, I'm providing the valid signal for the 640x480 alpha input port. At the moment I'm not running into deadlocks, and I belive that the "ready" signal which is going down at column 300 is due to one of the components(not sure which one) in the 800x600 stream's chain. Do you think that I should combine (and-ing) all 4 of the "ready" signals before providing the "valid" signal to the 640x480 alpha port ? In other words, should I stall the alpha values when any of the "ready" signals go low ? At the moment the "valid" signal is independant of the "ready" signals, I did try connecting the 640x480 source "ready" signal to it, but this distorted the video output. At the moment my main concern is how to provide the alpha values durring the "valid" low periods
