CYDC256B16, CYDC128B16,

CYDC064B16, CYDC128B08,

CYDC064B08

Switching Waveforms (continued)

Semaphore Read After Write Timing, Either Side[49, 50]

 

 

tSAA

tOHA

A0–A2

VALID ADRESS

VALID ADRESS

 

 

tAW

tACE

 

 

tHA

 

SEM

 

 

tSCE

tSOP

 

 

 

 

tSD

 

 

I/O0

DATAIN VALID

 

DATAOUT VALID

 

 

tSA

tHD

 

 

tPWE

 

 

R/W

 

 

 

 

tSWRD

tDOE

 

OE

 

tSOP

 

 

WRITE CYCLE

READ CYCLE

 

Timing Diagram of Semaphore Contention[51, 52]

A0L–A2L

R/WL

SEML

A0R–A2R

R/WR

SEMR

MATCH

tSPS

MATCH

Notes:

49.If the CE or SEM LOW transition occurs simultaneously with or after the R/W LOW transition, the outputs remain in the high-impedance state.

50.CE = HIGH for the duration of the above timing (both write and read cycle).

51.I/O0R = I/O0L = LOW (request semaphore); CER = CEL = HIGH.

52.If tSPS is violated, the semaphore will definitely be obtained by one side or the other, but which side will get the semaphore is unpredictable.

Document #: 001-01638 Rev. *E

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Cypress CYDC064B16, CYDC064B08 Semaphore Read After Write Timing, Either Side49, Timing Diagram of Semaphore Contention51