Fujitsu MAN3184 SERIES Specifications page 50

(20) Receive hold time
For ST data transfers the minimum time required at the receiving 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, provided P_CRCA is not transitioning with pCRC
protection enabled.
For DT data transfers the minimum time required at the receiving 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.
(21) Receive negation period
The minimum time required at a SCSI device receiving a REQ signal for the signal to be negated
while using synchronous data transfers. Also, the minimum time required at a SCSI device
receiving an ACK signal for the signal to be asserted while using synchronous data transfers. For
SE fast-5 and fast-10 operation, the time period is measured at the 2.0 V level. For SE fast-20
operation the period is measured at the 1.9 V level. For LVD see figure 1.19 and figure 1.20 for
signal measurement points.
(22) Receive setup time
For ST data transfers the minimum time required at the receiving 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 required at the receiving SCSI device between the
changing of the DB(15-0, P_CRCA, and/or P1) signals and the transition of the REQ or ACK
signals while using synchronous data transfers.
(23) Receive REQ(ACK) period tolerance
The minimum tolerance that a SCSI device should allow to be subtracted from the REQ(ACK)
period. The tolerance comprises the Transmit REQ(ACK) tolerance plus a measurement error due
to noise.
(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.
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