M54/M74HC192/193
INPUT AND OUTPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
PIN No
SYMBOL
NAME AND FUNCTION
3, 2, 6, 7
QA to QD Flip-Flop Outputs
4
5
CPD
CPU
Count Down Clock Input
Count Up Clock Input
11
LOAD
Asynchronous Parallel
Load Input (Active LOW)
12
13
14
CARRY
Count Up (Carry)
Output (Active LOW)
BORROW Count Down (Borrow)
Output (Active LOW)
CLEAR
Asynchronous Reset
Input (Active HIGH)
15, 1, 10, 9
DA to DD
GND
Data Inputs
8
Ground (0V)
16
VCC
Positive Supply Voltage
IEC LOGIC SYMBOL (HC191)
IEC LOGIC SYMBOL (HC193)
TRUTH TABLE
COUNT UP
COUNT DOWN
LOAD
CLEAR
FUNCTION
H
H
H
H
H
H
L
L
L
L
L
L
H
COUNT UP
NO COUNT
COUNT DOWN
NO COUNT
PRESET
H
H
X
X
X
X
X
RESET
X: Don’t Care
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STMICROELECTRONICS [ ST ]
