Fujitsu MBA3073 SERIES Technical Manual page 53

(24) Signal timing skew
The maximum signal timing skew occurs when transferring random data and in combination with
interruptions of the REQ or ACK signal transitions (e.g., pauses caused by offsets). The signal
timing skew includes cable skew (measured with 0101...patterns) and signal distortion skew
caused by random data patterns and transmission line reflections. The receiver detection range is
the part of the signal between the "may detect" level and the "shall detect" level on either edge.
(25) REQ (ACK) period
The REQ (ACK) period during synchronous data transfers is measured from an assertion edge of
the REQ (ACK) signal to the next assertion edge of the signal. In DT DATA phases the nominal
transfer period for data is half that of the REQ (ACK) period during synchronous data transfers
since data is qualified on both the assertion and negation edges of the REQ (ACK) signal. In ST
DATA phases the nominal transfer period for data is equal to the REQ (ACK) period during
synchronous data transfers since data is only qualified the assertion edge of the REQ (ACK)
signal.
(26) Transmit assertion period
The minimum time that a target shall assert the REQ signal while using synchronous data transfers
provided P_CRCA is not transitioning with pCRC protection enabled. Also, the minimum time
that an initiator shall assert the ACK signal while using synchronous data transfers.
(27) Transmit hold time
For ST data transfers the minimum time provided by the transmitting SCSI device between the
assertion of the REQ or ACK signal and the changing of the DB(15-0, P_CRCA, and/or P1)
signals while using synchronous data transfers.
For DT data transfers the minimum time provided by the transmitting SCSI device between the
transition (i.e. assertion or negation) of the REQ or ACK signals and the changing of the DB(15-0,
P_CRCA, and/or P1) signals while using synchronous data transfers.
(28) Transmit negation period
The minimum time that a target shall negate the REQ signal while using synchronous data
transfers provided P_CRCA is not transitioning with pCRC protection enabled. Also, the
minimum time that an initiator shall negate the ACK signal while using synchronous data transfers.
(29) Transmit setup time
For ST data transfers the minimum time provided by the transmitting SCSI device between the
changing of the DB(15-0, P_CRCA, and/or P1) signals and the assertion of the REQ or ACK
signal while using synchronous data transfers.
For DT data transfers the minimum time provided by the transmitting SCSI device between the
changing of the DB(15-0, P_CRCA, and/or P1) signals and the transition of the REQ or ACK
signal while using synchronous data transfers.
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