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Appendix A-10
Table A.4 Signal delay times definition (2/2)
No. Item Time Definition
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
11 Hold time 45 ns The minimum time added between the assertion of REQ (or
REQB) or ACK (or ACKB) and the changing of the data lines
to provide hold time in the initiator or target while using
synchronous data transfers. REQB and ACKB timings only
apply to optional wide data transfers.
12
Negation
period
90 ns
The minimum time that a target shall negate REQ (or REQB)
while using synchronous data transfers. Also, the minimum
time that an initiator shall negate ACK (or ACKB) while
using synchronous data transfers. REQB and ACKB timings
only apply to optional wide data transfers.
13 Power-on to
selection time
10 sec
(recom-
mended)
The recommended maximum time from power application
until an SCSI target is able to respond with appropriate status
and sense data to the TEST UNIT READY, INQUIRY, and
REQUEST SENSE commands
14
Reset to
selection time
250 ms
(recom-
mended)
The recommended maximum time after a hard RESET
condition until an SCSI target is able to respond with
appropriate status and sense data to the TEST UNIT READY,
INQUIRY, and REQUEST SENSE commands
15 Reset hold
time
25 µs The minimum time over which RST must be kept asserted
16
Selection abort
time
200 µs
The maximum time required from the moment when selection
or deselection of an initiator or target is detected until BSY is
asserted
17 Selection
timeout delay
250 ms
(recom-
mended)
The minimum time required for an initiator or target in the
selection or deselection phase to wait for a BSY response
before it starts the timeout procedure
18 Transfer period
-
The minimum allowable period, during sync data transfer,
between the start of consecutive REQ pulses and the start of
consecutive ACK pulses