LSI LSI53C896, Technical Manual

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5-10 SCSI SCRIPTS Instruction Set
OPC Opcode 27
This 1-bit field defines the instruction to execute as a
block move (MOVE).
Target Mode
The LSI53C896 verifies that it is connected to the SCSI
bus as a target before executing this instruction.
The LSI53C896 asserts the SCSI phase signals (SMSG/,
SC_D/, and SI_O/) as defined by the Phase Field bits in
the instruction.
If the instruction is for the command phase, the
LSI53C896 receives the first command byte and decodes
its SCSI Group Code.
•
If the SCSI Group Code is either Group 0,
Group 1, Group 2, or Group 5, then the LSI53C896
overwrites the
DMA Byte Counter (DBC) register with
the length of the Command Descriptor Block: 6, 10, or
12 bytes.
•
If the Vendor Unique Enhancement 0 (VUE0) bit
(
SCSI Control Two (SCNTL2) , bit 1) is cleared and the
SCSI group code is a vendor unique code, the
LSI53C896 overwrites the
DMA Byte Counter (DBC)
register with the length of the Command Descriptor
Block: 6, 10, or 12 bytes. If the VUE0 bit is set, the
LSI53C896 receives the number of bytes in the byte
count regardless of the group code.
OPC Instruction Defined
0 MOVE/MOVE64
1 CHMOV/CHMOV64
*