The Start-Of-Frame (SOF) signal, physically
transmitted over the AXI4-Stream
TUSER0 signal, marks the first pixel of a video
frame.
The SOF pulse is 1 valid transaction wide, and
must coincide with the first pixel of the frame, as seen in Figure 1.
The SOF signal serves as a frame
synchronization signal, which allows downstream cores to re-initialize, and detect the
first pixel of a frame. The SOF signal can be asserted
an arbitrary number of AP_CLK cycles before the first
pixel value is presented on DATA , as long as a VALID is not asserted.