M74HC670(1992) データシートの表示（PDF） - STMicroelectronics

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M74HC670
(Rev.:1992)

4 WORD X 4 BIT REGISTER FILE (3 STATE)

STMicroelectronics 

M54/M74HC670

WRITE FUNCTION TABLE

READ FUNCTION TABLE

WRITE INPUTS

WORDS

READ INPUTS

OUTPUTS

WB WA WE 0

1

2

3

RB RA RE Q0 Q1 Q2 Q3

L

L

L Q = D Q0 Q0 Q0

L

L

L W0B1 W0B2 W0B3 W0B4

L

H

L

Q0 Q = D Q0 Q0

L

H

L W1B1 W1B2 W1B3 W1B4

H

L

L

Q0 Q0 Q = D Q0

H

L

L W2B1 W2B2 W2B3 W2B4

H

H

L

Q0 Q0 Q0 Q = D

H

H

L W3B1 W3B2 W3B3 W3B4

X

X

H

Q0 Q0 Q0 Q0

X

X

H

Z

Z

Z

Z

Notes:

1 *: DON’T CARE Z: HIGH IMPEDANCE

2 (Q = D) = THE FOUR SELECT INTERNAL FLIP FLOP OUTPUTS WILL ASSUME THE STATES APPLIED TO THE FOUR

EXTERNAL DATA INPUTS.

3 Q0 = THE LEVEL OF Q BEFORE THE INDICATED INPUT CONDITIONS WERE ESTABLISHED.

4 W0B1 = THE FIRST BIT OF WORD 0, ETC.

LOGIC DIAGRAM

2/12

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