Atari 400 Basic Reference Manual

ADDRESS CONTENTS
Decimal Hexadecimal
4863
12FF
FILE
MANAGEMENT SYSTEM RAM (current DOS)
1792
700
1791
6FF
FREE RAM
1536
600
1535
5FF
FLOATING
POINT (used by BASIC)
1406 57E
1405
57D
BASIC CARTRIDGE
1152
480
1151 47F
] OPERATING SYSTEM RAM (47F-200)
3FD
CASSETTE BUFFER
1021
1020
3FC
RESERVED
1000 3E8
999
3E7
PRINTER BUFFER
960
3CO
959
3BF
J
IOCB's
832
340
831
33F
J
MISCELLANEOUS OS VARIABLES
512 200
511
1FF
HARDWARE STACK
256 100
255 FF
PAGE ZERO
FLOATING POINT (used by BASIC)
212 D4
211 D3
BASIC
or CARTRIDGE PROGRAM
210 D2
209
D1
FREE BASIC RAM
208
DO
207 CF
FREE BASIC
AND ASSEMBLER RAM
203
CB
202
CA
FREE ASSEMBLER
RAM }
176 BO
BASIC
128
80 ASSEMBLER ZERO PAGE
ZERO PAGE
127
7F
OPERATING SYSTEM RAM
0
0
As the addresses for the top of RAM, OS, and BASIC and the ends of OS and BASIC vary according to the
amount of memory, these addresses are indicated by pointers. The pointer addresses for each are defined
in Appendix I.
D-2 Appendix

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)