[Coco] Undocumented video modes
puritan_2076 at yahoo.com
Mon Feb 5 13:38:54 EST 2007
> There is also a wide 128 character text or 256 byte graphic screen using
> bit7 at $FF9F (horizontal virtual enable). Coupled with vertical
> scrolling can give you a graphics screen 256 bytes H by as large as your
> memory permits V.
Um...wow. 256 bytes wide means, at 2 bytes per pixel, 512X(192-225)-16. I was
sort of hoping for, but not taking seriously, the possibility of 16 colors
above 320X225. Now it looks like that's possible.
But wich is more amazing- 512X200-16, or 4-color mode, 1024X? It sounds almost
like you're even suggesting the possibility of 2-color, 2048X? How wide can it
I remember an article in rainbow that told how to use a 128-collum mode, but
it only displayed 80 collums at once. How wide can it really get on the
How high can it get on the monitor, without scrolling?
Is there a way to change the Sync rate of the GIME?
> Misuse of the switches may result in unexpected combinations of the
> above. That's not really undocumented as I think you mean it.
I first read about these strange modes on the "Gate Crasher" web site. You get
to shoot Bill in what is called an "undocumented" 128X192-16 mode. That's the
kind of stuff I was really expecting to find- more colors in the low-rez modes.
I also read what I think was a typo but might not have been that compared
NitrOS-9 to another speed upgrade using a 640X129-16 window. Is it possible?
> There really is no good way to use these mode from Basic. You have to
> write your own ml programs. The patching required to Basic would be
I was just thinking of using pokes, etc, like on the C=64, to try them out.
Maybe someday I'll actualy find an OS-9 Level II Development Pack with RMA.
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