Seagate Ultra 320, Ultra 160 manual Crosstalk time shift, ISI of data, ATN transmit setup time

Table 10: SCSI fast-160 and fast-320 interconnect timing budget in nanoseconds

	Item	Fast-160			Fast-320			Comments
Nominals:
	REQ(ACK) period		12.5			6.25		from table 6
	Transfer period		6.25			3.125		REQ(ACK) period/2
				Post			Post
		Total		Compens	Total		Compens	Worst case total of + and -
Transmitter and receiver errors:		Errors		ation	Errors		ation	time shift except where noted
Interconnect errors:
	Cable skew a b	2.5		0	2.5		0
	Crosstalk time shift	0.7		0.7	0.5		0.5	Time impact
	ISI of data	4.0		2.0	4.0		1.0	Worse case pattern
Total interconnect budget		7.2		2.7	7.0		1.5

aSee 2.5.8.

bThe residual deskew error is included in the receiver error budget.

Note. For more information on interconnect errors see the SCSI Passive Interconnect Performance standard.

2.5.1Arbitration delay

The minimum time a SCSI device shall wait from asserting BSY for arbitration until the data bus can be exam- ined to see if arbitration has been won (see Section 3.1.2). There is no maximum time.

2.5.2ATN transmit setup time

When information unit transfers are not being used, the ATN transmit setup time is the minimum time provided by the transmitter between the assertion of the ATN signal and the last negation of the ACK signal in any phase.

When information unit transfers are being used with synchronous transfers, the ATN transmit setup time is the minimum time provided by the transmitter between the assertion of the ATN signal and the negation of the ACK signal corresponding to the last iuCRC transfer of an information unit.

When information unit transfers are being used with paced transfers, the ATN transmit setup time is the mini- mum time provided by the transmitter between the assertion of the ATN signal and the assertion of the ACK signal corresponding to the last iuCRC transfer of an information unit.

Specified to provide the increased ATN receive setup time, subject to intersymbol interference, cable skew, and other distortions.

2.5.3ATN receive setup time

When information unit transfers are not being used, the ATN receive setup time is the minimum time required at the receiver between the assertion of the ATN signal and the last negation of the ACK signal in any phase to recognize the assertion of an attention condition.

26 Parallel SCSI Interface Product Manual, Rev. A )