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Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E
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2.2.3
Bus clear delay (800 ns)
The maximum time for a SCSI device to stop driving all bus signals after:
(1)
The Bus Free phase is detected (BSY and SEL both negated for a bus settle delay).
(2)
SEL is received from another SCSI device during the Arbitration phase.
(3)
The transition of RST to assertion.
Note.
For the first condition above, the maximum time for a SCSI device to clear the bus is 1200 ns
from BSY and SEL first becoming both negated. If a SCSI device requires more than a bus
settle delay to detect Bus Free phase, it shall clear the bus within a Bus Clear delay minus
the excess time.
2.2.4
Bus free delay (800 ns)
The minimum time that a SCSI device shall wait from its detection of the Bus Free phase (BSY and SEL both
negated for a bus settle delay) until its assertion of BSY when going to the Arbitration phase.
2.2.5
Bus set delay (1.8 µs)
The maximum time for a SCSI device to assert BSY and its SCSI ID bit on the Data Bus after it detects Bus
Free phase (BSY and SEL both negated for a bus settle delay) for the purpose of entering the Arbitration
phase.
2.2.6
Bus settle delay (400 ns)
The time to wait for the bus to settle after changing certain control signals as specified in the protocol defini-
tions.
2.2.7
Cable skew delay (10 ns)
The maximum difference in propagation time allowed between any two SCSI bus signals when measured
between any two SCSI devices.
2.2.8
Data release delay (400 ns)
The maximum time for an initiator to release the Data Bus signals following the transition of the I/O signal
from negation to assertion.
2.2.9
Deskew delay (45 ns)
The minimum time required for deskew of certain signals.
2.2.10
Disconnection delay (200 µs)
The minimum time that a target shall wait after releasing BSY before participating in an Arbitration phase
when honoring a Disconnect message from the initiator.
2.2.11
Hold time (45 ns)
The minimum time added between the assertion of REQ or ACK and the changing of the data lines to provide
hold time in the initiator or target, respectively, while using synchronous data transfers.
2.2.12
Negation period (90 ns)
The minimum time that a target shall negate REQ while using synchronous data transfers. Also, the minimum
time that an initiator shall negate ACK while using synchronous data transfers.
