Avago Technologies LSI53C1000R User Manual
Page 214
4-102
Registers
Version 2.2
Copyright © 2000–2003 by LSI Logic Corporation. All rights reserved.
XCLKH_ST
Extra Clock of Data Hold on ST Transfer Edge
2
Setting this bit adds a clock of data hold to synchronous
DT or ST SCSI transfers on the ST edge. This bit impacts
both ST and DT transfers as it affects data hold to the ST
edge. Setting this bit reduces the synchronous send
transfer rate but does not reduce the transfer rate at which
the LSI53C1000R can receive inbound REQs, ACKs or
data. Refer to
and
for a summary of
available transfer rates and to
through
for examples of how the XCLKH bits function.
Note:
This bit does not affect CRC timings.
XCLKS_DT
Extra Clock of Data Setup on DT Transfer Edge
1
Setting this bit adds a clock of data setup to synchronous
DT SCSI transfers on the DT edge. This bit only impacts
DT transfers as it only affects data setup to the DT edge.
Setting this bit reduces the synchronous transfer send
rate but does not reduce the transfer rate at which the
LSI53C1000R can receive inbound REQs, ACKs or data.
Refer to
and
for a summary of
available transfer rates and to
through
for examples of how the XCLKS bits function.
Note:
This bit does not affect CRC timings.
XCLKS_ST
Extra Clock of Data Setup on ST Transfer Edge
0
Setting this bit adds a clock of data setup to synchronous
DT or ST SCSI transfers on the ST edge. This bit impacts
both ST and DT transfers as it affects data setup to the
ST edge. Setting this bit reduces the synchronous send
transfer rate but does not reduce the transfer rate at which
the LSI53C1000R can receive inbound REQs, ACKs or
data. Refer to
and
for a summary of
available transfer rates and to
through
for examples of how the XCLKS bits function.
Note:
This bit does not affect CRC timings.
Synchronous Receive Rate Calculation
The synchronous receive rate, in megatransfers/s, can be
calculated using the following formula:
Receive Rate (DT)
Input Clock Rate
SCF Divisor
2
Ч
--------------------------------------------
=