Avago Technologies LSI53C896 User Manual
Page 141
SCSI Registers
4-29
Version 3.3
Copyright © 1998–2003 by LSI Logic Corporation. All rights reserved.
VUE1
Vendor Unique Enhancement, Bit 1
1
This bit disables the automatic byte count reload during
Block Move instructions in the command phase. If this bit
is cleared, the device reloads the Block Move byte count
if the first byte received is one of the standard group
codes. If this bit is set, the device does not reload the
Block Move byte count, regardless of the group code.
WSR
Wide SCSI Receive
0
When read, this bit returns the value of the Wide SCSI
Receive (WSR) flag. Setting this bit clears the WSR flag.
This clearing function is self-clearing.
The WSR flag indicates that the SCSI core received data
from the SCSI bus, detected a possible partial transfer at
the end of a chained or nonchained block move
command, and temporarily stored the high-order byte in
the
register rather than
passing the byte out the DMA channel. The hardware
uses the WSR status flag to determine what behavior
must occur at the start of the next data receive transfer.
When the flag is set, the stored data in SWIDE may be
“residue” data, valid data for a subsequent data transfer,
or overrun data. The byte is read as normal data by
starting a data receive transfer.
Performing a SCSI send operation clears this bit. Also,
performing any nonwide transfer clears this bit.