Write local register cache modifications to Datapixx at leading edge of next
video vertical sync pulse. This is a good way to write Datapixx registers with
microsecond synchronization to the start of a video frame. All Datapixx Set*
functions do fast writes to a local register cache on the host, and all Datapixx
Get* functions do fast reads from this local register cache. RegWrVideoSync
writes these cached register modifications back to the Datapixx over USB. The
cache writeback USB message is sent immediately and this function returns
quickly, but the Datapixx itself waits until the next vertical sync pulse before
writing the registers.
This call could be followed by a Screen(‘Flip’, win) command to synchronize
register writes to presentation of a new video image.
Note that if the Screen(‘Flip’, win, when) form is used, the new video image may
be delayed many frames after the register cache is written.
See DatapixxDacSyncDemo.m and DatapixxAdcAcquireDemo.m for examples.