DLPU048E August 2016 – July 2024
This test utilizes the video tell-tale checksum hardware to confirm that the video frame is being updated by the input graphics processor each frame. It cannot be executed at the same time as the video tell-tale checksum since they rely on the same hardware.
A pixel region is specified by host command and the checksum of the pixel data within that region must increment by 1 each frame until the value reaches its maximum value. Once the checksum has reached its maximum value, the value must roll over to 0 and the pattern repeats. If the value does not increment in a frame, the test will take action. The maximum and minimum frame count values are flash settings.
The following equation is used to calculate the checksum. For each pixel within the specified window, sum the red, green, and blue level and add it to the checksum.
CS(n) = ( CS(n-1) + R(n) + G(n) + B(n) ) & 0xFFFFFFFF
Where:
There are several possible implementations of this frame counter that can be used by a graphics processor to fulfill this test's requirements.