LSI53C875 LSI Logic, LSI53C875 Datasheet - Page 138

• Manufacturer Part Number: LSI53C875
• Description: PCI to Ultra SCSI I/O Processor
• Manufacturer: LSI Logic

5-22
Register: 0x0A (0x09)
SCSI Selector ID (SSID)
Read Only
VAL
R
ENDID[3:0]
Register: 0x0B (0x8B)
SCSI Bus Control Lines (SBCL)
Read Only
REQ
ACK
BSY
SEL
ATN
SCSI Operating Registers
REQ
VAL
7
0
7
x
ACK
6
6
x
x
SCSI Valid
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.
Reserved
Encoded Destination SCSI ID
Reading the
immediately after the LSI53C875 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.
SREQ/ Status
SACK/ Status
SBSY/ Status
SSEL/ Status
SATN/ Status
BSY
R
5
x
x
SCSI Selector ID (SSID)
SEL
4
4
x
x
ATN
3
0
3
x
MSG
0
2
x
ENID
register
C/D
0
1
x
I/O
0
0
0
x
[6:4]
[3:0]
7
7
6
5
4
3