Avago Technologies LSI53C895A User Manual
Page 242
5-20
SCSI SCRIPTS Instruction Set
this bit for the Select instruction. If this bit is set on any
other I/O instruction, an illegal instruction interrupt is
generated.
R
Reserved
[23:20]
ENDID[3:0]
Encoded SCSI Destination ID
[19:16]
This 4-bit field specifies the destination SCSI ID for an I/O
instruction.
R
Reserved
[15:11]
CC
Set/Clear Carry
10
This bit is used in conjunction with a Set or Clear
instruction to set or clear the Carry bit. Setting this bit
with a Set instruction asserts the Carry bit in the ALU.
Clearing this bit with a Clear instruction deasserts the
Carry bit in the ALU.
TM
Set/Clear Target Mode
9
This bit is used in conjunction with a Set or Clear
instruction to set or clear Target mode. Setting this bit
with a Set instruction configures the LSI53C895A as a
Target device (this sets bit 0 of the
register). Clearing this bit with a Clear
instruction configures the LSI53C895A as an Initiator
device (this clears bit 0 of the SCNTL0 register).
R
Reserved
[8:7]
ACK
Set/Clear SACK/
6
R
Reserved
[5:4]
ATN
Set/Clear SATN/
3
These two bits are used in conjunction with a Set or Clear
instruction to assert or deassert the corresponding SCSI
control signal. Bit 6 controls the SCSI SACK/ signal. Bit 3
controls the SCSI SATN/ signal.
The Set instruction is used to assert SACK/ and/or SATN/
on the SCSI bus. The Clear instruction is used to
deassert SACK/ and/or SATN/ on the SCSI bus. The
corresponding bit in the
register is set or cleared depending on the
instruction used.