Seagate Ultra 320 manual Scsi bus timing, Scsi bus control timing values in nanoseconds, Timing

2.5SCSI bus timing

Unless otherwise indicated, the delay time measurements for each SCSI device, defined in paragraphs 2.5.1 through 2.5.60 shall be calculated from signal conditions existing at that SCSI device’s own SCSI bus connec- tion. Thus, these measurements (except skew delay) can be made without considering delays in the cable. Refer to the tables below for the actual timing values for these delays.

Table 4:	SCSI bus control timing values in nanoseconds
				Timing
		Reference	Type	value (ns
				unless
Timing description
				noted)
Arbitration delay		2.5.1	minimum	2.4 µs
Bus clear delay		2.5.4	maximum	800
Bus free delay		2.5.5	minimum	800
Bus set delay		2.5.6	maximum	1.6 µs
Bus settle delay		2.5.7	minimum	400
Cable skew [1]		2.5.8	maximum	4
Data release delay		2.5.21	maximum	400
DIFFSENS voltage filter time		2.5.22	minimum	100 ms
Physical disconnection delay		2.5.24	minimum	200 µs
Power on to selection [2]		2.5.25	maximum	10 s
QAS arbitration delay		2.5.26	minimum	1000
QAS assertion delay		2.5.27	maximum	200
QAS release delay		2.5.28	maximum	200
QAS non-data phase REQ(ACK) period		2.5.29	minimum	50
Reset delay		2.5.42	minimum	200
Reset hold time		2.5.43	minimum	25 µs
Reset to selection [2]		2.5.44	maximum	250 ms
Selection abort time		2.5.46	maximum	200 µs
Selection time-out delay [2]		2.5.47	minimum	250 ms
System deskew delay		2.5.51	minimum	45

[1]Cable skew is measured at each SCSI device connection with the transmitted skew subtracted from the received skew.

[2]This is a recommended time. It is not mandatory.

20 Parallel SCSI Interface Product Manual, Rev. A )