LSI53C875 LSI Logic, LSI53C875 Datasheet - Page 177

• Manufacturer Part Number: LSI53C875
• Description: PCI to Ultra SCSI I/O Processor
• Manufacturer: LSI Logic

A one in any bit position of the final SLPAR value would indicate a
transmission error.
The
the check bytes for SCSI send operations. If the
(SLPAR)
contains the appropriate check byte at the end of the block move. This
byte must then be sent across the SCSI bus.
The longitudinal parity checks are meant to provide an added measure
of SCSI data integrity and are entirely optional. This register does not
latch SCSI selection/reselection IDs under any circumstances. The
default value of this register is zero.
Register: 0x45 (0xC5)
SCSI Wide Residue (SWIDE)
Read/Write
SWIDE
Data Bytes
1. 11001100
2. 01010101
3. 00001111
4. 10010110
7
x
SCSI Longitudinal Parity (SLPAR)
Note:
–
register contains all zeros prior to sending a block move, it
x
Writing any value to this register resets it to zero.
Running SLPAR
00000000
11001100 (XOR of word 1)
10011001 (XOR of word 1 and 2)
10010110 (XOR of word 1, 2 and 3) Even Parity
00000000
SCSI Wide Residue
After a wide SCSI data receive operation, this register
contains a residual data byte if the last byte received was
never sent across the DMA bus. It represents either the
first data byte of a subsequent data transfer, or it is a
residue byte which should be cleared when an Ignore
x
x
SWIDE
register is also used to generate
x
SCSI Longitudinal Parity
x
x
0
x
[7:0]
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