Registers: 0xd8–0xda, Register: 0xdb, Registers: 0xdc–0xdf – Avago Technologies LSI53C895A User Manual
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Registers
Registers: 0xD8–0xDA
SCSI Byte Count (SBC)
Read only
SBC
SCSI Byte Count
[23:0]
This register contains the count of the number of bytes
transferred to or from the SCSI bus during any given
BMOV. This value is used in calculating the information
placed into the
and
register and should not need to be
used in normal operations. There are two conditions in
which this byte count will not match the number of bytes
transferred exactly. If a BMOV is executed to transfer an
odd number of bytes across a wide bus then the byte
count at the end of the BMOV will be greater than the
number of bytes sent by one. This will also happen in an
odd byte count wide receive case. Also, in the case of a
wide send in which there is a chain byte from a previous
transfer, the count will not reflect the chain byte sent
across the bus during that BMOV. The reason for this is
due to the fact that to determine the correct address to
start fetching data from after a phase mismatch this byte
cannot be counted for this BMOV as it was actually part
of the byte count for the previous BMOV.
Register: 0xDB
Reserved
Registers: 0xDC–0xDF
Cumulative SCSI Byte Count (CSBC)
Read/Write
CSBC
Cumulative SCSI Byte Count
[31:0]
This loadable register contains a cumulative count of the
actual number of bytes that have been transferred across
23
0
SBC
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
31
0
CSBC
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0