Atari 800

Mixing Graphics Modes, cont.
II. PROCEDURE TO SET UP SCREEN IN MIXED MODES:
1. Select modes desired, then look up which mode is the max
RAM mode from table #2.
example:
modes selected - mode 1, mode 7, mode 2
mode 7 = max RAM mode
2. Use table #1 to calculate the number of mode lines such
that the total number of scan lines = 192.
example:
scan
lines
II
mode
per scan
mode
line mode
lines
line
1
6
8
48
7 56 2
11 2
2 2
16
32
192
TOTAL
3. If the max RAM mode is at the top of the screen, then skip
this step: Calculate the LMS byte by setting the left
nibble to 4, then use table #1 to find the right nibble for
the graphics mode at the top of the screen.
example:
1. left nibble = 4
2. right nibble for mode 1 6
3. LMS byte = 46 (HEX)
4 •
Calculate the mode byte for each
mode.
Set the left
nibble
to
0'
use table
Ill to
find the right nibble
for each
mode.
example:
I
Left
I
Right!
Hode
Model
Nibble! Nibble!
Byte
I
I I
(HEX)
1 0
6
06
7
0 D OD
2
0
7 07
B -3-