Tandy 1000 Technical Reference Manual

Tandy 1000
Table of Contents
Technical Reference Manual
Introduction .
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 3
Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5
Mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 6
Connector Pin Assignments .
1000 and IBM I/O Bus Cross Reference Chart .
Bus Interface Specifications .
7
10
13
Theory of Operation 17
Main Logic Board 17
IFL Equations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 21
Introduction to the Video System Logic. . . . . . . . . . . . . . . . . . . . .. 38
Video System Modes 45
Display Modes 45
Operating Modes 46
Graphics
Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 47
System Logic Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 50
Video Array Register " 50
Palette Mask
Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50
Border Color
Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 51
Mode Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 51
Palette Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52
Video
Memory Map Register .. . . . . . . . . . . . . . . . . . . . . . . .. 53
Mode Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 55
Color Select Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 55
Status Register . . . . . . . . . .
.. 56
CRT/Processor Page Register. . . . . . . . . . . . . . . . . . . . . . . .
.. 57
General
Memory Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 58
Mode Selection
Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 58
I/O
Map 58
System Configuration Port 59
ROM 59
RAM 59
Detailed Memory
Map 60

Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200