Fujitsu M3097DG, Руководство OEM

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A.3 Bus Phases
Appendix A-9
Table A.4 Signal delay times definition (1/2)
No. Item Time Definition
1 Arbitration
delay 2.4 µs The minimum time an SCSI device shall wait from asserting
BSY for arbitration until the DATA BUS can be examined to
see if arbitration has been won. There is no maximum time.
2
Assertion
period
90 ns
The minimum time that a target shall assert REQ (or REQB)
while using synchronous data transfers. Also, the minimum
time that an initiator shall assert ACK while using
synchronous data transfers.
3 Bus Clear
delay 800 ns The maximum time for an SCSI device to stop driving all bus
signals after:
(1) The BUS FREE phase is detected (BSY and SEL both
false for a bus settle delay)
(2) SEL is received from another SCSI device during the
ARBITRATION phase
(3) The transition of RST to true.
For the first condition listed, the maximum time for an SCSI
device to clear the bus is 1200 nanoseconds from BSY and
SEL first becoming both false. If an 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.
4 Bus free delay 800 ns The minimum time that an SCSI device shall wait from its
detection of the BUS FREE phase (BSY and SEL both false
for a bus settle delay) until its assertion of BSY when going to
the ARBITRATION phase.
5 Bus set delay 1.8 µs
The maximum time for an SCSI device to assert BSY and its
SCSI ID bit on the DATA BUS after it detects BUS FREE
phase (BSY and SEL both false for a bus settle delay) for the
purpose of entering the ARBITRATION phase
6 Bus settle
delay 400 ns The minimum time to wait for the bus to settle after changing
certain control signals as called out in the protocol definitions
7 Cable skew
delay 10 ns The maximum difference in propagation time allowed
between any two SCSI bus signals measured between any two
SCSI devices
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 false to
true
9 Deskew delay 45 ns The minimum time required for deskew of certain signals