LSI 53C810A User Manual
Page 129
5-55
A one in any bit position of the final
value would indicate a transmission error.
The
SCSI Longitudinal Parity (SLPAR)
register is also
used to generate the check bytes for SCSI send
operations. If the
SCSI Longitudinal Parity (SLPAR)
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 resets it to zero.
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: 0x46 (0xC6)
Memory Access Control (MACNTL)
Read/Write
TYP[3:0]
Chip Type
[7:4]
These bits identify the chip type for software purposes.
Bits 3 through 0 of this register are used to determine if
an external bus master access is to local or far memory.
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)
Even parity >>> 10010110
4. 10010110 00000000
7
4
3
2
1
0
TYP[3:0]
DWR
DRD
PSCPT
SCPTS
0
1
1
0
0
0
0
0