Tandy 1000 Technical Reference Manual

Tandy 1000
Technical Reference Manual
TYPE SN76494, SN76496
PROGRAMMABLE TONE/NOISE GENERATOR
electrical characteristics over recommended nmges of supply voltage and opeRlting free-air tampeRlture
RInge (unless otherwise noted)
PARAMETER TEST CONDITIONS
MIN TYP MAX UNIT
IoH
High-level output current (pin 4) 10 pA
'oL
Low-level output current (except pin 4) 2 mA
Input current
I
eE input
VI:O to Vee
-25 -175
I All other inputs
-10
-70
pA
VIB
Input bias yoltage, audio R- 4.7 kO pin 9 to Vee
0.5 0.7 0.9 V
VOH
High-level output voltage (except pin 4) 5.5 V
VOL
Low-level output voltage 0.25
0.4
V
Ice
SupplV current 30 50
mA
I
2 dB NOM
1
2
3
Anenuator
I
4 dB NOM
3
4
5
dB
I
BdBNOM 7
8
9
I
16 dB NOM
15
16
17
C;
Input capacitance
15 pF
switching characteristics, Vee =6 V, TA = 25°e
PARAMETER TEST CONDITIONS
MIN
TYP
MAX UNIT
lpHL
Progagation delav time. high-to-low level
eL : 225 pF, RL: 2 kO to Vee
90
150
READY output from CE
PARAMETER MEASUREMENT INFORMATION
VCC --------------._------,
SN76494
(16)
2kO
(6) (4)
t------:....'iINPUT OUTPUT ~~.- .... --~
225 pF
GND
(8)
FIGURE 1 - tpHL TEST CIRCUIT

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