RE: CBM 1541 (fwd)

From: Marko Mäkelä (
Date: 2000-11-17 09:33:08

On Fri, 17 Nov 2000, COPLIN, Nicholas. wrote:

> Interesting, I always assumed telling the VIC to "blank" automatically
> disabled all extra accesses....

No, it only disables the character code/colour fetches.  And if I remember
correctly, the VIC-II monitors the $d011 screen blank bit twice per frame:
once for determining whether the screen should be blanked, and another
time for deciding whether to draw characters on the screen.  It should be
possible to disable the screen and still get bad lines (not very useful,
isn't it?), and to disable the bad lines and get a screen with $d021
background color and black $3fff-shaped "characters" (i.e. similar to what
you get when opening the top/bottom borders).  This mode saves time if you
only need to display some information (in sprites).


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