Tandy 1000 Technical Reference Manual

PC MEMORY MAP
PCjr MEMORY MAP
TANDY 1 ~~~ MEMORY MAP
~3D~
~3DI
~3D2
~3D3
~3D4
6845 ADDRESS REGISTER
6845 ADDRESS REGISTER
6845 ADDRESS REGISTER
~3D5
6845 DATA REGISTER
6845 DATA REGISTER
6845 DATA REGISTER
~3D6
~3D7
~BD8
MODE SELECT REGISTER
NOT AVAILABLE
MODE SELECT REGISTER
~3D9
COLOR SELECT REGISTER
NOT AVAILABLE
COLOR SELECT
REGISTER
~3DA
READ STATUS REGISTER
WRITE GATE ARRAY ADDRESS, DATA
WRITE VIDEO ARRAY ADDRESS
& READ STATUS
& READ STATUS
~3DB
CLEAR LIGHT PEN LATCH
CLEAR LIGHT PEN LATCH
CLEAR LIGHT PEN LATCH
~3DC
PRESET LIGHT PEN LATCH PRESET LIGHT PEN LATCH
PRESET LIGHT PEN LATCH
~3DD
~3DE
WRITE VIDEO ARRAY DATA
~3DF
CRT PROCESSOR PAGE REGISTER
CRT PROCESSOR PAGE REGISTER
SYSTEM MEMORY READ = 1 WAIT
RAM READ/WRITE
~ 6 WAITS
RAM READ/WRITE
~ 2 WAITS
TIMING
I/O READ/WRITE =1 WAIT
ROM READ
= ~ WAITS
ROM READ
=0 WAITS
I/O READ/WRITE =0 WAITS
I/O READ/WRITE = 1 WAlTS
o
o
o

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