Since I read about the keyzone spectragram I've been trying to find any information and the only program that I could find that mentions it is Gazelle.

"Gazelle permits the online display of Viewdata frames in high-quality colour if you
have a IIGS and an analog RGB monitor. Viewdata frames can be displayed
offline in colour with a //e or //c double Hi-Res colour display. They may also be
viewed offline in colour on the //e by using a Keyzone Spectragram colour card
and RGB monitor."

If I run the gazelle communications program and put in a watchpoint for the c0f0-c0ff range (for slot 7) it gets hit at 4b17. (wp c0f0,f,rw)
Next thing it starts peeking at c0f2, so let's (find 0,bfff,f2,c0)

And we can find some code where it wants to write to c700 (which makes sense as the keyzone would sit in slot 7)

[Linked Image from i.imgur.com]
[Linked Image from i.imgur.com]

Knowing from an article that the keyzone has 8 bit color (2 bits blue, 3 bits for r and b) that these bit values seem to be initializing a color table.
If we take the upper 2 bits middle 3 and lower 3, this table translates to:

00 = 000
07 = 001
c0 = 100
C7 = 101
38 = 110
00 = 000
FF = 111
C7 = 101
00 = 000
00 = 000
00 = 000
FF = 111
00 = 000
3F = 011
F8 = 110
FF = 111

It looks like these would be 8 colors with each R G or B component set to 1 or 0, which would match the teletext colors, since that's what Gazelle was designed to view.

[Linked Image from i.imgur.com]
[Linked Image from i.imgur.com]
[Linked Image from i.imgur.com]
[Linked Image from i.imgur.com]

Left alt will bring up the menu.

If it finds a keyzone card it puts a nonzero value in 4aa5, if we set 4aa5=1 it will draw different bit patterns in the double hi-res space. Maybe the keyzone displays 140x192 without artifacts?

So it's most curious, just wish I could find a keyzone disk image/manual somewhere.

Last edited by Golden Child; 09/09/19 12:03 PM.