nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; j: whether joypad is ready to be read</PRE>
This register is pretty simple; it returns whether in a vertical/horizontal
blank period (1=yes) and whether the joypad is ready to be read from registers
$4218 to $421F.&nbsp; The horizontal blank time lasts from "pixels" 256
to 339. (Not really pixels, since nothing is being drawn.)&nbsp; In zSNES,
<I>apparently</I>, the joypad becomes ready to be read once every frame,
and more specifically, scanline 227 (might not be a const