Tandy 1000 Technical Reference Manual

Tandy 1000
Technical Reference Manual
8255A18255A·5
CONTROL WORD ,,13
D] 06 D~ 04 D
3
OJ 01 Do
1,1
0
I 0 I, [, 1
0
], I
CONTROL WOHD ::14
D
7
06 O~ 04 0 0 0 0
~'I"I:i"loOI
I -
c I
I
-PCJPC
o
,
f PS, PB
O
A _-- i-~
A--~PA7PAo
0, l\,_
I -
c i
I
I- -
BI-
Operating Modes
MODE 1 (Strobed Input/Output). This functional con-
figuration provides a means for transferring I/O data to
or from a specified port in conjunction with strobes or
"handshaking" signals. In mode 1, port A and Port B use
the lines on port C to generate or accept these "hand-
shaking" signals.
6-173
- P8
l
PS
o
Mode 1 Basic Functional Definitions'
• Two Groups (Group A and Group BI
•
Each group contains one 8-bit data port and one 4-bit
control/data porI.
• The 8-bit data port can be either input or output_
Both inputs and outputs are latched.
• The
4-bit port is used for control and status of the
8-bit data porI.

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