Philips Semiconductors

Product specification

74F552

Octal registered transceiver with parity and flags (3-State)

1991 Jan 02

4

R or S FLAG FUNCTION TABLE

INPUTS

OUTPUTS

OPERATING

CEX

CPX

OEXX

FR or FS

MODE

H

X

↑

NC

Hold flag

L

↑

↑

H

Set flag

X

X

↑

L

Clear flag

H = High voltage level

L = Low voltage level

NC= No change

X = Don’t care

X = R or S for CPX and CEX

XX= AS or BR

↑ = Low-to-High transition

↑ = Not Low-to-High transition

PARITY GENERATION FUNCTION TABLE

INPUTS

OUTPUTS

OEBR

CPR

Number of Highs

in the Q outputs

of the R register

PARITY

OPERATING

MODE

H

X

X

Z

Hold flag

L

L

↑

↑

0,2,4,6,8

1,3,5,7

H

L

Load data

H = High voltage level

L = Low voltage level

X = Don’t care

Z = High impedance “off” state

↑ = Low-to-High transition

PARITY CHECK FUNCTION TABLE

INPUTS

OUTPUTS

OEAS

CPS

PARITY

Number of Highs in the Q outputs

of the R register

ERROR

OPERATING MODE

H

L

L

L

L

X

↑

↑

↑

↑

X

L

L

H

H

X

0,2,4,6,8

1,3,5,7

0,2,4,6,8

1,3,5,7

H

L

H

H

L

Parity check

H = High voltage level

L = Low voltage level

X = Don’t care

↑ = Low-to-High transition