1-4
Introduction
•
Improved PCI Caching design - improves PCI bus efficiency.
•
Load/Store data transferred to or from SCRIPTS RAM internal to
chip.
•
Hardware control of SCSI activity LED.
•
Optional 944 byte DMA FIFO supports large block transfers at Ultra2
SCSI speeds. The default FIFO size of 112 bytes is also supported.
•
32-bit ISTAT registers (
Interrupt Status Zero (ISTAT0)
, and
1.2 Benefits of Ultra2 SCSI
Ultra2 SCSI is an extension of the SPI-2 draft standard that allows faster
synchronous SCSI transfer rates and defines a new physical layer, LVD
SCSI, that provides an incremental evolution from SCSI-2 and Ultra
SCSI. When enabled, Ultra2 SCSI performs 40 mega transfers per
second, which results in approximately double the synchronous transfer
rates of Ultra SCSI. The LSI53C896 can perform 16-bit, Ultra2 SCSI
synchronous transfers as fast as 80 Mbytes/s on each channel for a total
bandwidth of 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.
An advantage of Ultra2 SCSI is that it significantly improves SCSI
bandwidth while preserving existing hardware and software investments.
The primary software changes required are to enable the chip to perform
synchronous negotiations for Ultra2 SCSI rates, and to enable the clock
quadrupler. Ultra2 SCSI uses the same connectors as Ultra SCSI, but
can operate with longer cables and more devices on the bus.
contains more information on migrating an Ultra
SCSI design to an Ultra2 SCSI design.
1.3 Benefits of LVDlink
The LSI53C896 supports LVD for SCSI, a signaling technology that
increases the reliability of SCSI data transfers over longer distances than
are supported by SE SCSI. The low current output of LVD allows the I/O
transceivers to be integrated directly onto the chip. LVD provides the
*
Summary of Contents for LSI53C896
Page 6: ...vi Preface...
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Page 88: ...2 62 Functional Description...
Page 112: ...3 24 Signal Descriptions...
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Page 338: ...6 70 Specifications Figure 6 40 LSI53C896 329 BGA Bottom View...
Page 340: ...6 72 Specifications...
Page 346: ...A 6 Register Summary...
Page 362: ...IX 12 Index...