Philips Semiconductors

Product specification

74F191

Up/Down binary counter with reset and ripple clock

1995 Jul 17

4

MODE SELECT — FUNCTION TABLE

INPUTS

OUTPUTS

OPERATING MODE

PL

U/D

CE

CP

L

L

X

X

X

X

X

X

L

H

L

H

Parallel load

H

L

l

↑

X

Count up

Count up

H

H

l

↑

X

Count down

Count down

H

X

H

X

X

No change

Hold (do nothing)

TC AND RC FUNCTION TABLE

INPUTS

TERMINAL COUNT STATE

OUTPUTS

U/D

CE

CP

TC

RC

H

H

X

H

H

H

H

L

H

L

H

X

H

H

H

H

H

H

L

L

H

H

H

H

H

L

H

X

L

L

L

L

L

H

H

H

X

L

L

L

L

H

H

H

L

L

L

L

L

H

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