Radio Shack CCR-81 Technical Reference Manual

TABLE OF
CONTENTS
SECTION
PAGE
NUMBER
NUMBER
I
INTRODUCTION
1
System
Description
2
System
Block
Diagram
—
Illustration
3
Memory
Map
4
II
DISASSEMBLY/ASSEMBLY
11
Disassembly
12
Reassembly
12
Disassembly/Reassembly
—
Illustration
13
III
THEORY OF
OPERATION
15
6809E
CPU
16
6809E
Block Diagram
—
Illustration
16
6809E Programming
Model
—
Illustration
17
6809E
Typical Timing of Read/Write Cycles
—
Illustration
18
Reset Circuit
17
Dynamic Memory Control
19
MC6883
Block Diagram
—
Illustration
20
Timing
Diagram
—
Illustration
21
ROM
21
Video Interface
21
Mode
Selection
—
Table 1
24
Description of Display Modes
—
Table 2
25
Display
Character Set
—
Table 3
27
VDG
Video Output
—
Illustration
28
MC1372
Block Diagram
—
Illustration 28
Video Input to the
Modulator
—
Illustration 29
PIA's 29
PIA Block Diagram
—
Illustration
29
Digital
to
Analog
(D/A) 30
Joystick Interface 30
Sound Output
31
Sound Selection
—
Table
4
31
Sound
Circuity
—
Illustration 31
Cassette Interface 32
Sample Data
of
Cassette
Format
—
Illustration 32
Tape Format Information 32
RS-232C Interface
33
RS-232
Connector Pin-out
—
Illustration 33
Keyboard Interface
33
System Power Supply
33
723
Regulator Block Diagram
—
Illustration 34
Cartridge ROM and Other Devices 35
Cartridge Connector Signals
—
Table 5 36
ROM
Cartridge
Board
Schematic
—
Illustration 37
RS-232 Devices 38
Line Printer Variables
—
Table
6 38
Alternate Line Printer Variables
—
Table
7 39
Joysticks 40
Joystick
Schematic
—
Illustration
40
TV Switch Box
41
Antenna
Switch Box
Schematic
—
Illustration
41

Radio Shack CCR-81 Specifications

General

Brand	Radio Shack
Model	CCR-81
Category	Desktop
Language	English