Quantum 10K II - Manual (Page 328)

Appendix B. SCSI Bus Signal Timing
Quantum Atlas 10K II Ultra 160/m SCSI Hard Disk Drives B–7
The Timing Parameters and Descriptions for SCSI-3 ST/DT are defined in alphabetical order
below:
Arbitration delay - The minimum time a SCSI device shall wait from asserting the BSY signal for
arbitration until the DATA BUS is examined to see if arbitration has been won. There is no
maximum time.
ATN Transmit Setup Time - The minimum time provided by the transmitter between the
assertion of the ATN signal and the negation of the ACK signal.
ATN Receive Setup Time - The minimum time required at the receiver between the assertion of
the ATN signal and the negation of the ACK signal to recognize the assertion of an Attention
Condition.
Bus Clear Delay - The maximum time for a SCSI device to release all SCSI bus signals after:
a) the BUS FREE phase is detected (the BSY and SEL signals are both false for a bus settle
delay);
b) the SEL signal is received from another SCSI device during the ARBITRATION phase;
c) the transition of the RST signal to true.
For item a) 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.
Bus Free Delay - The minimum time that a SCSI device shall wait from its detection of the BUS
FREE phase (BSY and SEL both false for a bus settle delay) until its assertion of the BSY signal in
preparation for entering the ARBITRATION phase.
Bus 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.
Bus Settle Delay - The minimum time to wait for the bus to settle after changing certain
control signals as called out in the protocol definitions.
Cable Skew - The maximum difference in propagation time allowed between any two SCSI bus
signals measured between any two SCSI devices excluding any signal distortion skew delays.
pCRC Receive Hold Time - The minimum time required at the receiver between the transition of
the REQ signal and the transition of the P_CRCA signal while pCRC protection is enabled.
pCRC Receive Setup Time - The minimum time required at the receiver between the transition
of the P_CRCA signal and the transition of the REQ signal while pCRC protection is enabled.
pCRC Transmit Hold Time - The minimum time provided by the transmitter between the
transition of the REQ signal and the transition of the P_CRCA signal while pCRC protection is
enabled.
Receive Hold Time - For ST data transfers the minimum time required at the receiving SCSI
device between the assertion of the REQ signal or the ACK signals and the changing of the
DATA BUS while using synchronous data transfers.
For DT data transfers the minimum time required at the receiving SCSI device between the
transition (i.e. assertion or negation) of the REQ signal or the ACK signals and the changing of
the DATA BUS while using synchronous data transfers.