LSI technical manual TolerANT Technology, LSI53C875A Benefits Summary

Models: 53C875A

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synchronous negotiations for Ultra SCSI rates and to enable the clock quadrupler. Chapter 2, “Functional Description,”contains more information on Ultra SCSI design.

1.3 TolerANT® Technology

The LSI53C875A features TolerANT technology, which includes active negation on the SCSI drivers and input signal filtering on the SCSI receivers. Active negation actively drives the SCSI Request, Acknowledge, Data, and Parity signals HIGH rather than allowing them to be passively pulled up by terminators. Active negation is enabled by setting bit 7 in the SCSI Test Three (STEST3) register.

TolerANT receiver technology improves data integrity in unreliable cabling environments where other devices would be subject to data corruption. TolerANT receivers filter the SCSI bus signals to eliminate unwanted transitions, without the long signal delay associated with RC-type input filters. This improved driver and receiver technology helps eliminate double clocking of data, the single biggest reliability issue with SCSI operations.

The benefits of TolerANT technology include increased immunity to noise when the signal is going HIGH, better performance due to balanced duty cycles, and improved fast SCSI transfer rates. In addition, TolerANT SCSI devices do not cause glitches on the SCSI bus at power-up or power-down, so other devices on the bus are also protected from data corruption. TolerANT technology is compatible with both the Alternative One and Alternative Two termination schemes proposed by the American National Standards Institute.

1.4 LSI53C875A Benefits Summary

This section of the chapter provides an overview of the LSI53C875A features and benefits. It contains these topics:

SCSI Performance

PCI Performance

Integration

1-4

General Description

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LSI technical manual TolerANT Technology, LSI53C875A Benefits Summary