LSI53C875 LSI Logic, LSI53C875 Datasheet - Page 132

• Manufacturer Part Number: LSI53C875
• Description: PCI to Ultra SCSI I/O Processor
• Manufacturer: LSI Logic

5-16
Table 5.2
(MHz)
66.67
66.67
37.50
33.33
16.67
CLK
80
80
50
50
40
25
20
SCSI CLK
Bits [6:4]
SCNTL3
Examples of Synchronous Transfer Periods for SCSI-1 Transfer Rates
1.5
1.5
4
4
3
3
2
2
2
1
1
1
SCSI Operating Registers
Bits [7:5]
(SXFER)
XFERP
4
5
4
5
4
5
4
4
4
4
4
4
The LSI53C875 is connected to a hard disk which can
transfer data at 10 Mbytes/s synchronously. The
LSI53C875’s SCLK is running at 40 MHz. The
synchronous transfer period (SXFERP) is found as
follows:
Synchronous Send Rate = (SCLK/SCF)/XFERP
Synchronous Receive Rate = (SCKL/SCF)/4.
Where:
SCLK
SCF
Synch. Send
(Mbytes/s)
Rate
5.55
4.44
6.25
6.25
5.55
6.25
4.17
5
4
5
5
5
SCSI clock.
SCSI synchronous core frequency.
Period (ns)
Transfer
Synch.
200
250
180
225
160
200
200
160
180
160
200
240
Synch. Receive
Rate (Mbytes)
5.55
5.55
6.25
6.25
6.25
5.55
6.25
4.17
5
5
5
5
Period (ns)
Receive
Synch.
200
200
180
180
160
160
200
160
180
160
200
240