Atari 400 Hardware Manual

CHIP NAME
POKEY
PIA
FUNCTION
Keyboard scan and control
Serial communications port (bidirecti mal)
Pot scan (digitizes position of 8 indepen~~ n t pots)
Audio generation (4 channels)
Timers
IRQ (maskable interrupt) control from peripher? : s
Random number
generator
Controller (Joystick) jacks read or write
Peripheral control and interrupt lines
IRQ (maskable) interrupt control from peripherals
Section II describes the hardware in some detail, including the
various graphics modes. Section III lists the hardware registers one at a
time, describing what each bit is used for. It is organized by functional
groups (interrupts, graphics, audio, etc.). Section IV contains a sample
display program. Section V contains various figures and block diagrams of
the system. Sections VI and VII list the hardware registers in address
order and alphabetical order. Section VII includes hex and decimal
addresses, the OS shadow registers and the page numbers where more infor-
mation can be found.
1.2

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)