Seagate Ultra 160 Bus clear delay, Bus free delay, Bus set delay, Bus settle delay, Clock jitter

When information unit transfers are being used with synchronous transfers, the ATN receive setup time is the minimum time required at the receiver between the assertion of the ATN signal and the negation of the ACK signal corresponding to the last iuCRC transfer of an information unit to recognize the assertion of an attention condition.

When information unit transfers are being used with paced transfers, the ATN receive setup time is the mini- mum time required at the receiver between the assertion of the ATN signal and the assertion of the ACK signal corresponding to the last iuCRC transfer of an information unit to recognize the assertion of an attention condi- tion.

2.5.4Bus clear delay

The maximum time for a SCSI device to stop driving all bus signals after:

1.The BUS FREE phase is detected (i.e., the BSY and SEL signals are both false for a bus settle delay).

2.The SEL signal is received from another SCSI device during the ARBITRATION phase.

3.The transition of the RST signal to true.

For item 1 above, the maximum time for a SCSI device to release all SCSI bus signals is 1200 ns from the BSY and SEL signals first becoming both false. If a SCSI device requires more than a bus settle delay to detect BUS FREE phase, it shall release all SCSI bus signals within a bus clear delay minus the excess time.

2.5.5Bus free delay

The minimum time that a SCSI device shall wait from its detection of the BUS FREE phase (i.e., BSY and SEL both false for a bus settle delay) until its assertion of the BSY signal in preparation for entering the ARBITRA- TION phase.

2.5.6Bus set delay

The maximum time for a SCSI device to assert the BSY signal and its SCSI ID after it detects a BUS FREE phase for the purpose of entering the ARBITRATION phase.

2.5.7Bus settle delay

The minimum time to wait for the bus to settle after changing certain control signals as specified in the protocol definitions. Provides time for a signal transition to propagate from the driver to the terminator and back to the driver.

2.5.8Cable skew delay

The maximum difference in propagation time allowed between any two SCSI bus signals when measured between any two SCSI devices excluding any signal distortion skew delays.

2.5.9Chip noise in receiver

The maximum transition to transition time shift due to the internal physics of the receiving SCSI device circuitry.

2.5.10Clock jitter

The maximum transition to transition time shift of SCSI bus signals caused by short term variations in the trans- mitting SCSI device’s clock.

2.5.11Crosstalk time shift

The peak-to-peak timeshift error on DB(0-15), P_CRCA, or DB(P1) caused by transitions on all other DB(0- 15), P_CRCA, or DB(P1) signals.

Parallel SCSI Interface Product Manual, Rev. A ) 27