Avago Technologies LSI53C1030 - Manual (Page 50)

2-20 Functional Description
Version 2.2 Copyright © 2001, 2002, 2003 by LSI Logic Corporation. All rights reserved.
Figure 2.2 Paced Transfer Example
The LSI53C1030 uses the PPR negotiation that the SPI-4 draft standard
describes to establish a paced transfer agreement for each initiator-target
pair.
Precompensation – When transmitting in the Ultra320 SCSI mode, the
LSI53C1030 uses precompensation to adjust the strength of the REQ,
ACK, parity, and data signals. When a signal transitions to HIGH or LOW,
the LSI53C1030 boosts the signal drive strength for the first data transfer
period, and then lowers the signal drive strength on the second data
transfer period if the signal remains in the same state. The LSI53C1030
maintains the lower signal drive strength until the signal again transitions
HIGH or LOW.
Figure 2.3 illustrates the drivers performance with
precompensation enabled and disabled.
Data Not Valid Data Valid Data Valid Data Not Valid
REQ
ACK
P1
DATA