74hct191 NXP Semiconductors, 74hct191 Datasheet - Page 5

• Manufacturer Part Number: 74hct191
• Description: Presettable Synchronous 4-bit Binary Up/down Counter
• Manufacturer: NXP Semiconductors

Philips Semiconductors
FUNCTION TABLE
TC AND RC FUNCTION TABLE
Notes
1. H = HIGH voltage level
December 1990
parallel load
count up
count down
hold (do nothing)
Presettable synchronous 4-bit binary
up/down counter
L = LOW voltage level
I
X = don’t care
U/D
H
H
H
L
L
L
= LOW-to-HIGH CP transition
= LOW voltage level one set-up time prior to the LOW-to-HIGH CP transition
OPERATING MODE
= one LOW level pulse
= TC goes LOW on a LOW-to-HIGH CP transition
INPUTS
CE
H
H
H
H
L
L
CP
X
X
X
X
Q
PL
H
H
H
H
H
H
L
L
L
L
L
0
Fig.4 Functional diagram.
TERMINAL COUNT STATE
U/D
X
X
H
X
L
Q
H
H
H
L
L
L
5
1
INPUTS
CE
X
X
H
I
I
Q
H
H
H
L
L
L
2
CP
X
X
X
Q
H
H
H
L
L
L
D
3
H
X
X
X
L
n
74HC/HCT191
OUTPUTS
Q
L
H
count up
count down
no change
n
TC
Product specification
H
H
L
L
OUTPUTS
RC
H
H
H
H