Atari 400 Hardware Manual

Hardware Register
OS ;;;hadow
Address
Address
Name Description
Hex
Dec
Name
Hex
Dec
M3PF
Missile
3 to Playfield
Collisions D003
53251
M3PL
Missile
3 to
Player
DOOB
53259
NMIEN
Non-Maskable Interrupt
(NMI) Enable
D40E 54286 Set to $40 by IRQ
code
NMIRES
NMI reset
D40F
54287
written to by NMI
code
NMIST
NMI Status
D40F 54287 read by NMI code
POPF
Player 0 to
Playfield Collisions
D004 53252
I
POPL
Player 0 to Player Collisions
DOOC
53260
PlPF
Player 1 to Playfield Collisions
D005 53253
PlPL
Player
1
to Player Collisions
DODD 53261
P2PF
Player
2
to Plavfield Collisions
D006 53254
P2PL
Player 2 to
Player Collisions DOOE 53262
P3PF
Player
3 to Playfield Collisions
D007 53255
P3PL Player
3 to Player Collisions
DOOF 53263
PACTL
Port A Control
D302 54018 Set to
$3C
by IRQ
Code
PAL PAL/NTSC indictor D014 53268
I I
PBCTL Port B Control
D303 54019 Set to $3C by IRQ Code
PENH Light Pen Horizontal Position
D40C 54284 LPENH 234 564
PENV Light Pen Vertical Position D40D
54285
LPENV
235 565
PMBASE Player Missile Base Address
D407 54279
PORTA Port A
D300
54016
STICKO.l
278.279
632 633
PORTB
Port A D301 54017 STICK2,3 27A, 27B 634,635
POTO
Pot 0
D200 53760
PADDLO
270,
624
POTl
Pot 1 D201
53761
PADDLl
271
625
POT2 Pot
2
D202
53762
PADDL2 272
626
~
POT3 Pot 3 D203
53763 PADDL3 273
627
POT4
Pot 4 D204
53764 PADDL4 274
628
POTS Pot 5
D205 53765
PADDL5 275
629
POT6
Pot 6 D206
53766
PADDL6 276
630
POT7 Pot
7
(right paddle controller)
D207 53767
PADDL7 277
631
POT GO
Start POT Scan Sequence
D20B 53771
WRITTEN
DURING VB LANK
PRIOR
Priority Select DOlB 53275
GPRIOR
26F 623
RANDOM Random number generator D20A 53770
SERIN Serial Port Input D20E 53774
SEROUT Serial Port output D20D 53773
SIZEM Sizes for all missiles DOOC
53260
SIZEPO Size
of Player 0
D008
53256
SIZEPl
Size
of Player 1 D009 53257
SIZEP2
Size of
Player 2 DOOA 53258
SIZEP3
Size of Player 3 DOOB 53259
SKCTL Serial Port Control
D20F 53775 SSKCTL 232 562
SKREST
Reset Serial Port Status
(SKSTAT)
D20A 53770
SKSTAT
Serial Port Status D20F 53775
STIMER
Start Timer
D209
53769
TRIGO Joystick Controller Trigger 0 DOlO 53264 STRIGO 284 644
TRIGl
Jovstick
Controller
Trigger
1
DOll 53265
STRIGL 285 645
TRIG2 Joystick Controller
Trigger
2
D012 53266
STRIG2 286
646
TRIG3T Joystick Controller Trigger
3
D013 53267
STRIG3 287 647
VCOUNT Vertical Line Counter
D40B
54283
VDELAY Verical Delay
DOlC
54276
VSCROL Vertical Scroll D405 54277
WSYNC Wait for Horizontal
Sync D40A 54282
Used by
keyboard
click routine
v. 6

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)