Avago Technologies LSI53C825AE User Manual
Page 194
5-10
SCSI SCRIPTS Instruction Set
– If the SCSI Group Code is either Group 0, Group 1,
Group 2, or Group 5, and if the Vendor Unique
Enhancement 1 (VUE1) bit (
, bit 1) is clear, then the LSI53C825A
overwrites the
register
with the length of the Command Descriptor Block:
6, 10, or 12 bytes.
– If the Vendor Unique Enhancement 1 (VUE1) bit
, bit 1) is set, the
LSI53C825A receives the number of bytes in the
byte count regardless of the group code.
– If the Vendor Unique Enhancement 1 bit is clear
and group code is vendor unique, the LSI53C825A
receives the number of bytes in the count.
– If any other Group Code is received, the
register is not modified and the
LSI53C825A requests the number of bytes
specified in the
register.
If the
register contains
0x000000, an illegal instruction interrupt is
generated.
4. The LSI53C825A transfers the number of bytes
specified in the
register
starting at the address specified in the
register. If the Opcode bit is set and
a data transfer ends on an odd byte boundary, the
LSI53C825A stores the last byte in the
register during a receive operation.
This byte is combined with the first byte from the
subsequent transfer so that a wide transfer can be
completed.
5. If the SATN/ signal is asserted by the Initiator or a
parity error occurred during the transfer, the transfer
can optionally be halted and an interrupt generated.
The Disable Halt on Parity Error or ATN bit in the
register controls
whether the LSI53C825A halts on these conditions
immediately, or waits until completion of the current
Move.