LSI LSI53C895A, Technical Manual

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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
SCSI Control Zero
(SCNTL0) 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
SCSI Output Control Latch
(SOCL) register is set or cleared depending on the
instruction used.