Commodore PC 20 - Page 60

44 Operations Guide
3d8: (write only)
bit 0: 0 = 40 x 25 text
1 = 80 x 25 text
bit 1: 0 = text mode
1 = graphics mode
bit 2: 0 = color mode
1 = blw mode
bit 3: 0 = disable video
1
= enable video
bit 4: 0 = non-640 x 200 b/w mode
1 = 640 x 200 b/w mode
bit 5: 0 = keep background intensity attribute bit
1 = change background intensity attribute bit
to blink bit
bit 6-7: unused
3d9: (write only)
bit O:-selects blue border color in 40 x 25, 80 x 25 text,
320 x 20016 colors or 640 x 20016 colors mode;
-selects blue as background color in 320 x 200 4 colors
or 640 x 200 4 colors mode
-selects blue as foreground color in 640 x 200 black
and white mode
bit 1 :-selects green border color in 40 x 25, 80 x 25 text,
320 x 20016 colors or 640 x 20016 colors mode;
-selects green as background color in 320 x 200
4
colors or 640 x 200 4 colors mode
-selects green as foreground color in 640 x 200 black
and white mode
bit 2:-selects red border color in 40 x 25, 80 x 25 text,
320 x 200 16 colors or 640 x 200 16 colors mode;
-selects red as background color in 320 x 200 4 colors
or 640 x 200 4 colors mode
-selects red as foreground color in 640 x 200 black and
white mode
bit 3:-selects intensified border color in 40 x 25,80 x 25
text,
320 x 200 16 colors or 640 x 200 16 colors
mode;
-selects intensified as background color in 320 x 200
4 colors or 640 x 200 4 colors mode
-selects intensified as foreground color in 640 x 200
black
and white mode
bit 4:-selects intensified set of foreground colors in 320 x
200 4 colors or 640 x 200 4 colors mode
c