er controls the way data is uploaded to VRAM.&nbsp; The bits
in here are a bit weird, but can be useful.&nbsp; When you want to change
only the high byte of a series of VRAM locations (register $2116 * 2 +
1), you should set i to 1.&nbsp; When you want to change just the low byte,
set i to 0.&nbsp; When you want to write a whole word, you should set i
to 0; otherwise, if i=1, writing a word will cause the high byte of the
first location to be changed, followed by the low byte of the next location.

<P>The r