5-12
SCSI SCRIPTS Instruction Set
If the SCSI phase bits match the value stored in the
register, the LSI53C896 transfers
the number of bytes specified in the
register starting at the address pointed to by the
register. If the opcode bit is
cleared and a data transfer ends on an odd byte
boundary, the LSI53C896 stores the last byte in the
register during a receive
operation, or in the
register during a send operation. This byte is combined
with the first byte from the subsequent transfer so that a
wide transfer can complete.
If the SCSI phase bits do not match the value stored in
the
register, the LSI53C896
generates a phase mismatch interrupt and the instruction
is not executed.
During a Message-Out phase, after the LSI53C896 has
performed a select with Attention (or SATN/ is manually
asserted with a Set ATN instruction), the LSI53C896
deasserts SATN/ during the final SREQ/SACK/
handshake.
When the LSI53C896 is performing a block move for
Message-In phase, it does not deassert the SACK/ signal
for the last SREQ/SACK/ handshake. Clear the SACK/
signal using the Clear SACK I/O instruction.
SCSIP[2:0]
SCSI Phase
[26:24]
This 3-bit field defines the desired SCSI information
transfer phase. When the LSI53C896 operates in the
initiator mode, these bits are compared with the latched
SCSI phase bits in the
register. When the LSI53C896 operates in the target
mode, it asserts the phase defined in this field. The
following table describes the possible combinations and
the corresponding SCSI phase.
*
Summary of Contents for LSI53C896
Page 6: ...vi Preface...
Page 16: ...xvi Contents...
Page 88: ...2 62 Functional Description...
Page 112: ...3 24 Signal Descriptions...
Page 306: ...6 38 Specifications This page intentionally left blank...
Page 310: ...6 42 Specifications This page intentionally left blank...
Page 338: ...6 70 Specifications Figure 6 40 LSI53C896 329 BGA Bottom View...
Page 340: ...6 72 Specifications...
Page 346: ...A 6 Register Summary...
Page 362: ...IX 12 Index...