December 1990

4

Philips Semiconductors

Product specification

8-bit parallel-in/serial-out shift register

74HC/HCT166

FUNCTION TABLE

Notes

1. H = HIGH voltage level

h = HIGH voltage level one set-up time prior to the LOW-to-HIGH CP transition

L = LOW voltage level

I = LOW voltage level one set-up time prior to the LOW-to-HIGH CP transition

q = lower case letters indicate the state of the referenced output one set-up time prior to the

LOW-to-HIGH CP transition

X = don’t care

↑ = LOW-to-HIGH CP transition

OPERATING MODES

INPUTS

OUTPUT

PE

CE

CP

parallel load

I

I

I

I

↑

↑

X

X

I- I

h - h

L

H

L - L

H - H

L

H

serial shift

h

h

I

I

↑

↑

I

h

X - X

X-X

L

H

hold “do nothing”

X

h

X

X

X - X

Fig.4 Functional diagram.