Midscreen scroll/parallax/character bank change glitching?

[ulfalizer]

In case it hasn't been mentioned, changing the vscroll (which requires setting loopy_v), switching banks, or doing other stuff that affects rendering "immediately" probably can't be done without glitching during the last 20 ticks or so of hblank, as the first two tiles for the next scanline are fetched there - so the safe window might be slightly narrower than you expect.

The diagram I made in viewtopic.php?f=3&t=9901&start=30 might clarify this.

[tepples]

x=256-320 is still plenty of window. Only the last two writes absolutely have to be within the window, and there are 5 cycles (15-16 dots) from the beginning of one write to the end of the second, that still leaves 48 dots, or 15-16 cycles.