Fujitsu MAW3073 SERIES Specifications page 74

The TARG must response to the INIT by asserting the BSY signal within Selection Abort Time
since the TARG detects that the TARG is selected. If the SCSI ID with three or more bits is
detected, or if a parity error is detected under the system that the parity bit is enabled, the TARG
shall not respond to the SELECTION phase.
At least Deskew Delay × 2 after the BSY signal (asserted by the TARG) detection, the INIT shall
release SEL signal. The values on the DATA BUS can be changed after this time.
Note:
When Selection without using attention condition, if an INIT detects an unexpected
COMMAND phase, it invalidates all prior negotiations with the selected TARG.
In this case, the INIT should create an attention condition and on the corresponding
MESSAGE OUT phase should issue an ABORT TASK message.
On the next selection of the TARG that received the ABORT TASK message the INIT
should do a selection using the attention condition.
With using attention condition, if an information unit transfer agreement is in effect for
the connecting INIT the TARG proceeds to a MESSAGE OUT phase. If the first message
received by the TARG during the MESSAGE OUT phase is not a TARGET RESET
message or a PPR message the TARG will change to a MESSAGE IN phase and issue a
MESSAGE REJECT message then originate WDTR negotiation with the TRANSFER
WIDTH EXPONENT field set to 00h.
(5) Timeout procedure
If the INIT cannot detect the response from TARG when the Selection Timeout Delay or longer
has passed after starting the SELECTION phase, the timeout procedure shall be performed through
one of the following schemes:
a) The case of creating Reset condition
The INIT should assert the RST signal.
b) The case of no response from the selected TARG
1) The INIT should continue asserting the SEL signal.
2) If the INIT creates an attention condition, The INIT should keep ATN signal asserted.
3) The INIT should release DB(15-0,P_CRCA,and/or P1).
4) If the INIT has not detected the BSY signal to be true after at least one Selection Abort
Time plus two System Deskew Delays, the INIT should release the SEL signal and ATN
signal (if Selection using attention condition) allowing the SCSI bus to go to the BUS
FREE phase.
5) SCSI devices should ensure that when responding to selection was still valid within one
Selection Abort Time of their assertion of the BSY signal.
6) Failure to comply with this requirement could result in an improper selection (two TARG
connected to the same INIT, wrong TARG connected to an INIT, or a TARG connected to
no INIT).
1-56 C141-C011