The following hardware restrictions apply and need to be taken care of by software:
- When AF is enabled software can not use the first or last pixels in the window. Start at position 2 end at line -2.
- When AEW is enabled software can not use the first pixel in a window. Start at position 2.
- (PAXW+1) % (AFINCH+1) != 1 when VF enabled (PAXW and AFINCH are raw MMR parameters)