Avago Technologies LSI53C896 - Manual (Page 147)

SCSI Registers 4-35
Version 3.3 Copyright © 1998–2003 by LSI Logic Corporation. All rights reserved.
MO[4:0] Max SCSI Synchronous Offset [4:0]
These bits describe the maximum SCSI synchronous
offset used by the LSI53C896 SCSI function when
transferring synchronous SCSI data in either the initiator
or target mode.
Table 4.5 describes the possible
combinations and their relationship to the synchronous
data offset used by the LSI53C896 SCSI function. These
bits determine the LSI53C896 SCSI function’s method of
transfer for Data-In and Data-Out phases only. All other
information transfers occur asynchronously.
Table 4.4 Example Transfer Periods and Rates for Fast SCSI-2,
Ultra, and Ultra2
CLK (MHz)
SCSI CLK
÷
SCNTL3 Bits [6:4] XFERP
Synch. Transfer
Period (ns)
Synch. Transfer
Rate (Mbytes)
160 1 4 25 40
160 2 4 50 20
160 4 4 100 10
80 1 4 50 20
50 1 4 80 12.5
50 1 4 100 10.0
40 1 4 100 10.0
37.50 1 4 106.67 9.375
33.33 1 4 120 8.33
25 1 4 160 6.25
20 1 4 200 5
16.67 1 4 240 4.17