LSI 20160 - Manual (Page 16)

1-4 Describing the LSI20160
Copyright © 2001 by LSI Logic Corporation. All rights reserved.
1.2.3 Board Characteristics
The board characteristics are
•
PCI board dimensions
Approximately 4.721 x 2.536 inches
•
Universal 32-bit PCI card edge connector
•
Standard bracket available
1.2.4 SCSI Activity LED Interface
The J3 connector is a four-wire arrangement on the LSI20160 that
represents the SCSI activity LED interface.
Table 3.5 on page 3-8 lists
the signal name and pin numbers for this LED interface.
1.3 Ultra160 SCSI Benefits
Ultra160 SCSI is an extension of the SPI-3 draft standard that allows
faster synchronous SCSI data transfer rates than Ultra2 SCSI. When
enabled, Ultra160 SCSI performs 80 megatransfers per second resulting
in approximately double the synchronous data transfer rates of Ultra2
SCSI. The LSI53C1000 performs 16-bit, Ultra160 SCSI synchronous
data transfers as fast as 160 Mbytes/s. This advantage is most
noticeable in heavily loaded systems or large block size applications
such as video on-demand and image processing.
1.3.1 Double Transition (DT) Clocking
The Ultra160 data transfer speed is accomplished using DT clocking.
DT clocking refers to transferring data on both rising and falling edges of
the request and acknowledge signals. Double-edge clocking doubles
data transfer speeds without increasing the clock rate.