Quantum Instruments DLT 7000 manual Scsi Description Scsi Bus Timing Values, Arbitration

SCSI Description

Table 3–4 SCSI Bus Timing Values (continued)

Timing Description	Value	Description
Bus Clear Delay	800 ns	Maximum time for a SCSI device to stop driving all
		bus signals after:
		1. BUS FREE is detected.	2.
		SEL is received from another SCSI device during
		ARBITRATION.	3.
		Transition of RST to true.
		For condition 1, the maximum time for a SCSI device
		to clear the bus is 1200 ns (1.2 μs) from BSY and SEL
		first becoming both false.
		If a SCSI device requires more than a bus settle delay
		to detect BUS FREE, it clears the bus within a bus clear
		delay minus the excess time.
Bus Free Delay	800 ns	Maximum time a SCSI device waits from its detection
		of BUS FREE until its assertion of BSY when going to
		ARBITRATION.
Bus Set Delay	1.8 µs	Maximum time for a device to assert BSY and its SCSI
		ID bit on the DATA BUS after it detects BUS FREE to
		enter ARBITRATION.
Bus Settle Delay	400 ns	Minimum time to wait for the bus to settle after
		changing certain control signals as called out in the
		protocol definitions.
Cable Skew Delay	10 ns	Maximum difference in propagation time allowed
		between any two SCSI bus signals measured between
		any two SCSI devices.
Data Release Delay	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.
Deskew Delay	45 ns	Minimum time required to wait for all signals
		(especially data signals) to stabilize at their correct,
		final value after changing.
Disconnection Delay	200 µs	Minimum time that a drive waits after releasing BSY
		before participating in an ARBITRATION when
		honoring a DISCONNECT message from the initiator.

3-8 Quantum DLT 7000 Tape System