m54hc191 STMicroelectronics, m54hc191 Datasheet - Page 2

• Manufacturer Part Number: m54hc191
• Description: 4 Bit Synchronous Up/down Counters
• Manufacturer: STMicroelectronics

M54HC191
IEC LOGIC SYMBOLS
INPUT AND OUTPUT EQUIVALENT CIRCUIT
TRUTH TABLE
X : Don’t Care
a - d: The level of steady state inputs a through d respectively
2/13
LOAD
H
H
H
H
L
ENABLE
H
X
L
L
X
INPUTS
D/U
X
H
X
X
L
CLOCK
X
QA
a
PIN DESCRIPTION
DOWN COUNT
QB
15, 1, 10, 9
NO CHANGE
NO CHANGE
b
3, 2, 6, 7
UP COUNT
OUTPUTS
PIN N°
12
13
14
16
11
4
5
8
QC
c
MA/MI OUT Terminal Count Output
SYMBOL
QA to QD
DA to DD
ENABLE
CLOCK
LOAD
RCO
GND
V
D/U
CC
QD
d
Flip-Flop Outputs
Count Enable Input
(Active LOW)
Parallel Data Input
Load Input (Active LOW)
Ripple Clock Output
(Active LOW)
Clock Input (LOW to
HIGH, edge triggered)
Data Inputs
Ground (0V)
Positive Supply Voltage
NAME AND FUNCTION
DOWN COUNT
PRESET DATA
NO COUNT
NO COUNT
FUNCTION
UP COUNT