TP2

TP1

TP0

XFERP

 

 

 

 

0

0

0

4

 

 

 

 

0

0

1

5

 

 

 

 

0

1

0

6

 

 

 

 

0

1

1

7

 

 

 

 

1

0

0

8

 

 

 

 

1

0

1

9

 

 

 

 

1

1

0

10

 

 

 

 

1

1

1

11

 

 

 

 

Use the following formula to calculate the synchronous send and receive rates. Table 5.3 and Table 5.4 show examples of possible bit combinations.

Synchronous Send Rate = (SCLK/SCF)/XFERP

Synchronous Receive Rate = (SCLK/SCF) /4

Where:

SCLK

SCSI clock

SCF Synchronous Clock Conversion Factor,

SCNTL3 register, bits [6:4]

XFERP Transfer period, SXFER register, bits [7:5]

Table 5.3 Examples of Synchronous Transfer Periods and Rates for SCSI-1

 

SCF ÷

 

 

 

Synch.

 

 

XFERP

Synch.

Synch.

Receive

Synch.

SCLK

SCNTL3

SXFER

Send Rate

Send

Rate

Receive

(MHz)

Bits [6:4]

Bits [7:5]

(Mbytes/s)

Period (ns)

(Mbytes/s)

Period (ns)

 

 

 

 

 

 

 

66.67

3

4

5.55

180

5.55

180

 

 

 

 

 

 

 

66.67

3

5

4.44

225

5.55

180

 

 

 

 

 

 

 

50

2

4

6.25

160

6.25

160

 

 

 

 

 

 

 

50

2

5

5

200

6.25

160

 

 

 

 

 

 

 

5-13

Page 87
Image 87
LSI 53C810A technical manual TP2 TP1 TP0 Xferp