Avago Technologies LSI53C825AE - Manual (Page 127)

Operating Registers 4-39
Register: 0x0A (0x09)
SCSI Selector ID (SSID)
Read Only
VAL SCSI Valid 7
If VAL is asserted, then the two SCSI IDs are detected
on the bus during a bus-initiated selection or reselection,
and the encoded destination SCSI ID bits below are valid.
If VAL is deasserted, only one ID is present and the
contents of the encoded destination ID are meaningless.
R Reserved [6:4]
ENID[3:0] Encoded Destination SCSI ID [3:0]
Reading the SCSI Destination ID (SDID) register
immediately after the LSI53C825A is selected or
reselected returns the binary-encoded SCSI ID of the
device that performed the operation. These bits are
invalid for targets that are selected under the single
initiator option of the SCSI-1 specification. This condition
is detected by examining the VAL bit above.
Register: 0x0B (0x8B)
SCSI Bus Control Lines (SBCL)
Read Only
REQ Assert SCSI REQ/ Signal 7
ACK Assert SCSI ACK/ Signal 6
BSY Assert SCSI BSY/ Signal 5
SEL Assert SCSI SEL/ Signal 4
ATN Assert SCSI ATN/ Signal 3
7 6 4 3 0
VAL R ENID[3:0]
0 x x x 0 0 0 0
7 6 5 4 3 2 1 0
REQ ACK BSY SEL ATN MSG C/D I/O
x x x x x x x x