LSI 53C875A User Manual
SCSI Registers
4-33
shows example transfer periods and rates for fast SCSI-2 and
Ultra SCSI.
MO[4:0]
Max SCSI Synchronous Offset
[4:0]
These bits describe the maximum SCSI synchronous
offset used by the LSI53C875A when transferring
synchronous SCSI data in either the initiator or target
mode.
offset used by the LSI53C875A when transferring
synchronous SCSI data in either the initiator or target
mode.
describes the possible combinations and
their relationship to the synchronous data offset used by
the LSI53C875A. These bits determine the
LSI53C875A’s method of transfer for Data-In and
Data-Out phases only; all other information transfers
occur asynchronously.
the LSI53C875A. These bits determine the
LSI53C875A’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
and Ultra SCSI
and Ultra SCSI
CLK (MHz)
SCSI CLK
÷
SCNTL3
Bits [6:4]
XFERP
Synch.
Transfer
Period (ns)
Synch. Transfer
Rate
(Mbytes/s)
160
1
1. Only with 40 MHz clock.
2
4
50
20
160
1
4
4
100
10
80
1
4
50
20
50
1
4
80
12.5
50
1
5
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