Table 3–4 Scsi Bus Timing Values - Quantum DLT 8000 Product Manual

Table 3–4 SCSI Bus Timing Values (continued)
Timing Description
Bus Settle Delay
Cable Skew Delay
Data Release Delay
Deskew Delay
Disconnection Delay
Hold Time
Negation Period
Power-On to Selection
Reset to Selection
Time
Reset Hold Time
Selection Abort Time
Selection Time-out
Delay
1
Recommended Time.
Value Description
400 ns Minimum time to wait for the bus to settle after
changing certain control signals as called out in the
protocol definitions.
10 ns Maximum difference in propagation time allowed
between any two SCSI bus signals measured between
any two SCSI devices.
400 ns Maximum time for an initiator to release the DATA BUS
signals following the transition of the I/O signal from
false to true.
45 ns Minimum time required to wait for all signals (especially
data signals) to stabilize at their correct, final value after
changing.
200 µs Minimum time that a drive waits after releasing BSY
before participating in an ARBITRATION when honoring a
DISCONNECT message from the initiator.
45 ns Minimum time added between the assertion of REQ or
ACK and changing the data lines to provide hold time in
the initiator or drive while using standard (slow)
synchronous data transfers.
90 ns Minimum time that a drive negates REQ while using
synchronous data transfers; also, the minimum time than
an initiator negates ACK while using synchronous data
transfers. 1
10 s 1 Recommended maximum time from power application
until a drive is able to respond with appropriate status
and sense data to the TEST UNIT READY, INQUIRY, and
REQUEST SENSE commands.
250 Recommended maximum time after a hard RESET
ms 1 condition until a drive is able to respond with
appropriate status and sense data to the TEST UNIT
READY, INQUIRY, and REQUEST SENSE commands.
25 µs Minimum time for which RST is asserted; there is no
maximum time.
200 µs Maximum time that a drive (or initiator) takes from its
most recent detection of being selected (or reselected)
until asserting a BSY response.
250 Recommended minimum time a SCSI device should wait
ms 1 for a BSY response during SELECTION or RESELECTION
before starting the time-out procedure.
Quantum DLT 8000 Tape System
SCSI Description
3-9