Tandy 1000 Programmer's Reference Guide

Chapter 1 I System Calls
Conio
Direct Console I/O Function Call 06H
Returns a keyboard input character if one is ready, or
outputs a character
to the video display. No check for
CONTROL-C is made on the character.
Entry Conditions:
AH = 06H
DL
= FFH: return character typed at the keyboard; if
avai
1 able
DL
# FFH: display character in DL
Exit Conditions:
If DL = FFH on entry:
Zero flag set and AL
= OOH if no key was pressed
Zero flag not set and
AL = keyboard input charac-
ter,
if available
If DL
# FFH on entry:
Character in DL is on screen
Macro Definition:
dir-console-io
macro switch
mov dl dwitch
mov ah, 06H
int 21 H
endm
38

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