first edition, first print

In English

Publisher: Radio Shack, 1978

Radio Shack catalog no. 26-2103

Table of Contents

Introduction	7
System Block Diagram Description	9
The Memory Map	12
THEORY OF OPERATION	14
CPU Address Lines	16
CPU Data Bus	17
CPU Control Group	18
System RAM	24
Video Divider Chain	28
Video RAMs	34
Video Processing	34
Keyboard	44
Input and Ouput Port	44
System Power Supply	52
Level II ROMs	55
ADJUSTEMENTS AND TROUBLESHOOTING	57
THE OUTSIDE WORLD	83
Memory mapped External Device	86
Port Based External Device	88
Explanation of Expansion Port Signals	90
Pin COnnections for Expansion Port Edge Card	91
PARTS LIST	93
SCHEMATIC	99
BASIC I ROMs	100
BASIC II ROMs	104
TSR-80 Master Schematic	107