Seagate Ultra160 Product Manual page 132

114
The detection of a BUS FREE phase following a SPI data stream information unit by a SCSI initiator shall be
equivalent to the initiator port receiving a DISCONNECT message.
The detection of a QAS REQUEST message following a SPI data stream information nit by a SCSI initiator
shall be equivalent to the initiator receiving a DISCONNECT message.
To end a sequence of SPI data stream information units, a SCSI initiator may request a disconnect by estab-
lishing an attention condition. The initiator shall continue to transfer or receive data, pad bytes (if any), and
iuCRCs until the target changes to the MESSAGE OUT phase.
During a sequence of SPI data stream information units the offset count is not required to go to zero at the
boundary of any SPI data stream information unit if the next SPI information unit is a SPI data stream informa-
tion unit.
Table 52: SPI status data stream information unit
Bit 7
Byte
0 MSB
n
n+1 MSB
n+2
n+3
n+4
[1] The Data field may contain any type of information (e.g., parameter lists, mode pages, user data).
[2] The iuCRC field shall use the algorithm defined in Subsection 11.3 of ANSI SCSI Parallel Interface (SPI-
4). If the iuCRC Interval field of the SPI L_Q information unit contains a value greater than zero and less
than the data length, then there is an iuCRC field at each iuCRC interval in addition to the iuCRC shown in
this table. These additional iuCRC fields are not shown in this table.
6 5
SCSI Interface Product Manual, Rev. B
4 3
Data [1]
iuCRC [2]
2 1
LSB
LSB
0