Philips Semiconductors
Up/Down binary counter with reset and ripple clock
Product specification
74F191
MODE SELECT — FUNCTION TABLE
INPUTS
PL
U/D
CE
CP
L
X
X
X
L
X
X
X
H
L
l
↑
H
H
l
↑
H
X
H
X
OUTPUTS
Dn
Qn
L
L
H
H
X
Count up
X
Count down
X
No change
TC AND RC FUNCTION TABLE
INPUTS
TERMINAL COUNT STATE
U/D
CE
CP
Q0
Q1
Q2
H
H
X
H
H
H
L
H
X
H
H
H
L
L
H
H
H
L
H
X
L
L
L
H
H
X
L
L
L
H
L
L
L
L
H = High voltage level steady state
L = Low voltage level steady state
X = Don’t care
= Low pulse
↑ = Low-to-High clock transition
l = Low voltage level one set-up time prior to the Low-to-High clock transition
OPERATING MODE
Parallel load
Count up
Count down
Hold (do nothing)
OUTPUTS
Q3
TC
RC
H
L
H
H
H
H
H
H
L
L
H
L
H
H
L
H
1995 Jul 17
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