Atari 800XL Service Manual

Peripheral Interface Arlantnr ( PIA1
The PIA
is a
general
purpose
Input/Output
(
I/O) chip.
It
monitors
the
X-Y
controller
interfaces
and the
SIO
control
lines.
In
certain
applications
it
may
control
the
MMU
logic.
Ground
VSS
1
•
40
Controller
Input
PAp
2
39
Controller
Input
PA1
3
38
Controller
Input
PA2
4
37
Controller
Input
PA3
5
36
Controller
Input
PA4
6
35
Controller
Input
PA5
7
34
Controller
Input
PA6
8
33
Controller
Input
PA7
9
32
Enable/Disable
Output
PBd
10
31
Not
Used
PB1
11
30
Output
to LED
1
PB2
12
29
Not
Used
PB3
13
28
Not
Used
PB4
14
27
Not
Used
PB5
15
26
Not
Used
PB6
16
25
Self
Test
Output
PB7
17
24
Control
Line
CB1
18
23
Command
Output
CB2
19
22
+5V
Supply
Voltage
VCC
20
21
CA1
Control
Line
CA2
Motor
Control
Output
TKQK
Interrupt
Request
(Out)
w
Interrupt
Request
(Out)
A1
Address
Line
A
0
Address
Line
W5
FT
Reset
Input
DO
Data
Line
D1
Data
Line
D2
Data
Line
D3
Data
Line
D4
Data
Line
D5
Data
Line
D6
Data
Line
D7
Data
Line
02
Clock
Input
CS1
Chip
Select
Input
Z52
Chip
Select
Input
CS0
Chip
Select
Clock
Input
R/¥
Read/Write
PIA
14

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