Avago Technologies LSI53C1030 - Manual (Page 23)

Benefits of Ultra320 SCSI 1-7
Version 2.2 Copyright © 2001, 2002, 2003 by LSI Logic Corporation. All rights reserved.
bytes in the sequence. The LSI53C1030 clocks PCI-X data directly into
and out of registers, which creates a more efficient data path. The
LSI53C1030 increases bus efficiency since it does not insert wait states
after the initial data phase when acting as a PCI-X target and never
inserts wait states when acting as a PCI-X initiator.
1.4 Benefits of Ultra320 SCSI
Ultra320 SCSI is an extension of the SPI-4 draft specification that allows
faster synchronous SCSI data transfer rates than Ultra160 SCSI. When
enabled, Ultra320 SCSI performs 160 megatransfers per second
resulting in approximately double the synchronous data transfer rates of
Ultra160 SCSI. The LSI53C1030 performs 16-bit, Ultra320 SCSI
synchronous data transfers as fast as 320 Mbytes/s on each SCSI
channel. This advantage is most noticeable in heavily loaded systems or
large block size applications, such as video on-demand and image
processing.
Ultra320 SCSI doubles both the data and clock frequencies from
Ultra160 SCSI. Due to the increased data and clock speeds, Ultra320
SCSI introduces skew compensation and intersymbol interference (ISI)
compensation. These new features simplify system design by resolving
timing issues at the chip level. Skew compensation adjusts for timing
differences between data and clock signals caused by cabling, board
traces, etc. ISI compensation enhances the first pulse after a change in
state to ensure data integrity.
Ultra320 SCSI includes CRC, which offers higher levels of data reliability
by ensuring complete integrity of transferred data. CRC is a 32-bit
scheme, referred to as CRC-32. CRC guarantees detection of all single
or double bit errors, as well as any combination of bit errors within a
single 32-bit range.