Atari 800XL Service Manual

MECHANICAL THFORV
The
800XL
computer
console
contains
a
single
motherboard
which
houses
all
the
chips
of the
system
and
provides
connectors
for
interfacing
external
modules
to
the
console.
It
includes
the
CPU
,
RAM
,
OS
and
BASIC
ROM's.
The
motherboard
uses
a
common
address
bus,
data
bus
aid
clock
lines.
The
sixteen-line
address
bus
allows
the
microprocessor
to
directly
address
64K
memory
locations.
The
eight-
line
data
bus
provides
the
communication
and
data
path
between
the
functional
modules.
The
power
is
provided
by
an
external
power
supply
and
routed
throughout
the
console
The
keyboard
is
the
user
interface
with
the
computer.
The
keyboard
connects
to
the
PC
Board
by
a
24-connector
ribbon
cable.
All
peripherals
connect
to the
800XL
either
through
the
SIO
connector
or
the
PBI.
Power
enters
through
the
7-Pin
DIN
connector
on
the
rear
panel.
Power
On/Off
is
controlled
by the
ON/OFF
switch
on
the
rear
panel.
RF
to
the TV
switchbox
arrives
from
an
RCA
phonoconnector
and
RF
cable.
Composite
Video
composite
luminance,
and
audio
signals
to
the
monitor
arrive
from
a 5
pin
DIN
monitor
jack
on
the
reer
panel.
ELECTRICAL THFORV
DIGITAL
HARDWARE
The
digital
hardware
consists
of:
*
The
6502C
CPU
microprocessor
*
The
Alphanumeric
Television
Interface
Controller
(ANTIC)
*
The
Graphics
Television
Interface
Adaptor
( GTIA)
*
The
POT
KEYboard
Intecrated
Circuit
(
POKEY)
*
The
Peripheral
Interface
Adaptor
(PIA)
*
The
Memory
(Operating
System
ROM
,
64K RAM
,
Atari
BASIC
ROM
,
Rev.
B)
*
Miscellaneous
Logic
Memory
Management
Unit
(
MMU)
Delay
Line
*
Parallel
Bus
Interface
(
PBI
)
9

Atari 800XL Specifications

General

Manufacturer	Atari
Type	Home computer
Release year	1983
CPU	MOS Technology 6502C
RAM	64 KB
ROM	24 KB
Operating System	Atari OS
CPU Speed	1.79 MHz (NTSC) / 1.77 MHz (PAL)
Graphics	ANTIC and GTIA chips
Display resolution	160×192 to 320×192 pixels
Sound	POKEY chip
Storage	Cassette tape, floppy disk
Ports	Serial, parallel, monitor, joystick ports