Atari 400 Hardware Manual

APPENDIX A
USE OF PLAYER / MISSILE GRAPHICS
\'liTH BASIC
The ATARI ® 400/800 1M Hardware ManuaJ should be read first to understand
the details of the Player/Missile Graphics.
To enable the P/M Graphics from BASIC the following procedure
can be used:*
1. Generate the playfield, either with a GRAPHICS call or build
a custom display list with a series of POKE statements.
2. Enable P/M DMA control by a POKE 559 with either a 62 for
single line resolution players or a 46 for double line
resolution players.
3.
There are four players and four missiles (or five players if
the four missiles are combined into one player). Each of
these has a horizontal position register that controls its
horizontal position on the screen . . The registers and their
locations are as follows:
ADDRESS
HORIZONTAL POSITION OF
53248
Player
0
53249
Player l
53250
Player 2
53251
Player
3
53252
Missile 1
53253
Missile 2
53254
Missile
3
53255 Missile 4
The
horizontal positions can range on the playfield between 41
and 200. So POKE 53249,120 will move Player 1 to the middle
of the screen.
*NOTE: All number references are decimal.
A-1-

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)