3

MODE SELECT - FUNCTION TABLE FOR ’HC161 AND ’HCT161

OPERATING MODE

INPUTS

OUTPUTS

MR

CP

PE

TE

SPE

TC

Reset (Clear)

L

XXXXX

L

L

Parallel Load

H

↑

XX

l

l

L

L

H

↑

X

X

l

h

H

(Note 1)

Count

H

↑

h

h

h (Note 3)

X

Count

(Note 1)

Inhibit

H

X

I (Note 2)

X

h (Note 3)

X

(Note 1)

H

X

X

I (Note 2)

h (Note 3)

X

L

MODE SELECT - FUNCTION TABLE FOR ’HC163 AND ’HCT163

OPERATING MODE

INPUTS

OUTPUTS

MR

CP

PE

TE

SPE

TC

Reset (Clear)

l

↑

XXXX

L

L

Parallel Load

h (Note 3)

↑

XX

l

l

L

L

h (Note 3)

↑

X

X

l

h

H

(Note 1)

Count

h (Note 3)

↑

h

h

h (Note 3)

X

Count

(Note 1)

Inhibit

h (Note 3)

X

I (Note 2)

X

h (Note 3)

X

(Note 1)

h (Note 3)

X

X

I (Note 2)

h (Note 3)

X

L

H = High voltage level steady state; L = Low voltage level steady state; h = High voltage level one setup time prior to the Low-to-High clock

transition; l = Low voltage level one setup time prior to the Low-to-High clock transition; X = Don’t Care; q = Lower case letters indicate the

state of the referenced output prior to the Low-to-High clock transition;

↑ = Low-to-High clock transition.

NOTES:

1. The TC output is High when TE is High and the counter is at Terminal Count (HHHH for HC/HCT161 and ’HC/HCT163).

2. The High-to-Low transition of PE or TE on the ’HC/HCT161 and the ’HC/HCT163 should only occur while CP is HIGH for conventional

operation.

3. The Low-to-High transition of SPE on the ’HC/HCT161 and SPE or MR on the ’HC/HCT163 should only occur while CP is HIGH for

conventional operation.

CD54/74HC161, CD54/74HCT161, CD54/74HC163, CD54/74HCT163