SCSI Registers
4-83
Register: 0x44
SCSI Longitudinal Parity (SLPAR)
Read/Write
SLPAR
SCSI Longitudinal Parity
[7:0]
This register performs a bytewise longitudinal parity
check on all SCSI data received or sent through the SCSI
core. If one of the bytes received or sent (usually the last)
is the set of correct even parity bits, SLPAR should go to
zero (assuming it started at zero). As an example,
suppose that the following three data bytes and one
check byte are received from the SCSI bus (all signals
are shown active HIGH):
A one in any bit position of the final SLPAR value would
indicate a transmission error.
The SLPAR register is also used to generate the check
bytes for SCSI send operations. If the
register contains all zeros prior to sending
a block move, it contains the appropriate check byte at
the end of the block move. This byte must then be sent
across the SCSI bus.
Note:
Writing any value to this register clears it to zero.
7
0
SLPAR
x
x
x
x
x
x
x
x
Data Bytes
Running SLPAR
–
00000000
1. 11001100 11001100 (XOR of word 1)
2. 01010101 10011001 (XOR of word 1 and 2)
3. 00001111 10010110 (XOR of word 1, 2 and 3)
4. 10010110 00000000
*
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...