Table 5.3 Examples of Synchronous Transfer Periods and Rates for SCSI-1 (Cont.)

 

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)

 

 

 

 

 

 

 

40

2

4

5

200

5

200

 

 

 

 

 

 

 

37.50

1.5

4

6.25

160

6.25

160

 

 

 

 

 

 

 

33.33

1.5

4

5.55

180

5.55

180

 

 

 

 

 

 

 

25

1

4

6.25

160

6.25

160

 

 

 

 

 

 

 

20

1

4

5

200

5

200

 

 

 

 

 

 

 

16.67

1

4

4.17

240

4.17

240

 

 

 

 

 

 

 

Table 5.4 Examples of Synchronous Transfer Periods and Rates for Fast SCSI

 

SCF ÷

XFERP

 

Synch.

Synch.

 

 

SXFER

Synch.

Send

Receive

Synch.

SCLK

SCNTL3

Bits

Send Rate

Period

Rate

Receive

(MHz)

Bits [6:4]

[7:5]

(Mbytes/s)

(ns)

(Mbytes)

Period (ns)

 

 

 

 

 

 

 

66.67

1.5

4

11.11

90

11.11

90

 

 

 

 

 

 

 

66.67

1

5

8.88

112.5

11.11

90

 

 

 

 

 

 

 

50

1

4

12.5

80

12.5

80

 

 

 

 

 

 

 

50

1

5

10

100

12.5

80

 

 

 

 

 

 

 

40

1

4

10

100

10.0

100

 

 

 

 

 

 

 

37.50

1

4

9.375

106.67

9.35

106.67

 

 

 

 

 

 

 

33.33

1

4

8.33

120

8.33

120

 

 

 

 

 

 

 

25

1

4

6.25

160

6.25

160

 

 

 

 

 

 

 

20

1

4

5

200

5

200

 

 

 

 

 

 

 

16.67

1

4

4.17

240

4.17

240

 

 

 

 

 

 

 

R

Reserved

4

MO[3:0]

Max SCSI Synchronous Offset

[3:0]

These bits describe the maximum SCSI synchronous offset used by the LSI53C810A when transferring synchronous SCSI data in either the initiator or target mode. Table 5.5 describes the possible combinations and their relationship to the synchronous data offset used by

5-14

Operating Registers

Page 88
Image 88
LSI 53C810A technical manual Reserved MO30 Max Scsi Synchronous Offset, Sclk SCNTL3