Atari 400 Hardware Manual

Mixing Graph ic s ~odes, c ~ nt.
II. PROCEDURE TO SET UP SCRE :::N H : HXED MODES, cont.:
5. Convert all bytes to decimal.
example: Bvte (HEX)
DEC
LMS 46
70
Mode 1
06 6
Mode 7
OD
13
Mode 2
07
7
6. Execute a graphics
mode (+16).
call on the computer using the max RAM
example: GRAPHICS 7 + 16
7. PEEK the Display List pointer and use it to calculate a
variable labelled "START".
example: START PEEK(560) + PEEK(561) * 256 + 4
8. If the max RAM mode is at the top of the screen, then skip
this step: Poke the LMS byte to location START-1.
example:
POKE START-1,70
9. Every mode line requires a mode byte in the Display List in
the same order as the mode line E &ppear on the screen. The
mode bytes must be POKED into the Display List at location
START + offset, where offset mode line #.
Example: MODE LINE # POKE INSTRUCTION
2
POKE
START +
2' 6
3
POKE START +
3' 6
MODE 1 4 POKE START
+
4,6
5
POKE
START +
5,6
6 POKE START +
6' 6
MODE 7 see note
for
mode
7
(max RAM
mode)
MODE 2
63 POKE START +
6 3' 7
64
POKE START
+
64,7
NOTE: _ The Display List will alre a dy be correct for the max RAM
mode, ' therefore its mode bytes do not need to be POKEd.
B -4-

Atari 400 Specifications

General

Manufacturer	Atari
Model	400
Type	Home Computer
Release Year	1979
CPU	MOS Technology 6502
CPU Speed	1.79 MHz
ROM	10 KB
Operating System	Atari OS
Keyboard	Membrane keyboard
RAM	8 KB (expandable to 48 KB)
Graphics	ANTIC and GTIA chips
Sound	4 channels
Display	RF output for connection to TV
Storage	Optional cassette tape drive or floppy disk drive
Ports	Cartridge
Display Resolution	320x192 (16 colors)