Tandy 1000 Programmer's Reference Guide

Appendix C I MS-DOS Memory Map
The structure and usage of the RS232 driver RAM data area is
as follows:
HEX Offset From
Segment 004000
Length and
Intended Use
OOH
7CH
4 words - Base address of each one of 4
possible comm cards
4 words - 1 word timeout count for
each of
4 possible comm
cards
The structure and usage of the Keyboard driver RAM data area
is as follows:
HEX Offset From Length and
Segment 0040:0010 Intended Use
17 1 byte - Keyboard shift state flag
returned by function 02
6 - CAPS LOCK on/off,
5 - NUM LOCK ordoff,
4 - SCROLL LOCK doff,
3 - ALT key depressed,
2
- CTRL key depressed,
1 - Left SHIFT key
0 - Right SHIFT key
bits
7 - INSERT state active,
depressed,
depressed
18 1 byte - Secondary shift state flag
bits INSERT key depressed,
6 - CAPS LOCK depressed,
5 - NUM LOCK depressed,
4 - SCROLL LOCK NUM
LOCK depressed,
4 - SCROLL depressed,
4 - SCROLL LOCK
depressed,
3 - Pause ordoff, depressed,
3 - Pause on/off,
2,1,0 - not used
232

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