HD74LS191

Rev.2.00, Feb.18.2005, page 6 of 10

Count Sequences

13

14

15

0

Load

Ripple

Clock

Inhibit

Count Down

Count Up

12

2

1

0

15

14

13

Load

Clock

Down/Up

Max/Min

Enable G

B

A

C

D

Illustrated below is the following sequence:

1.

Load (preset) to binary thirteen.

2.

Count up to fourteen, fifteen (maximum), zero, one and two.

3.

Inhibit

4.

Count down to one, zero (minimum), fifteen, fourteen, and thirteen.