Atari 800 - Page 266

264 User's H andbook to the Atari 400/ 800 Comp ut ers
Table 9-1. Atari Graphics Modes
Gr a phic
No. of
No . of
Mode
Mode
No . of
Rows
Rows
No. of R AM
Number
Type
Column s
(Split
Screen) (Full Screen)
Colors Requirement
0 TEXT 40 24
l' 993
1
TE XT 20 20
24
5 513
2
TEXT 20 10
12
5
26 1
3
GRAPH I CS 40
20 24 4
273
4
GRAPH I CS 80 40 48
2
537
5
GRAPH I CS 80 40 48
4
1017
6
GRAPH I CS
160
80
96 2
2025
7
GRAPH I CS
160
80
96 4
3945
8
GRAPH I CS
320
160
192
l ' 7900
'1 col or; 2 luminances
Mode 0 is the text mode. This is the sta nd ard mode that is
e ncount ered upon power-on.
Modes 0 conta ins a 24 by 40 character screen. The l eft margin is
set by default to column 2, and the right margin is set to co lumn
39. Th ese sett in gs allow 38 characters per lin e. The l eft and right
margins ca n be altered by POKEing a new location to the
me mory l ocatio ns which spec if y these margins.
The
left margin m emory address is known as LMARGN and is
address 82. The ri g ht margin memory addr ess is kn ow n as
RMARGN and is address 83 .
In Graphics Mode 0, on ly one col or is ava ilab le in the display
area. H owever, 2 diff e rent levels of lumin ance (brig htn ess) are
available. The co lor of the characters wi ll be the same as that of
the background. H owever, the luminanc e of the characters can
differ, making them r ea dable.