Seagate Ultra 320 ユーザーズマニュアル

Parallel SCSI Interface Product Manual, Rev. A )                                       

   43

The Transfer Period Factor field selects the transfer period and determines which transfer rate’s timing values 
in Tables 5, 6, 7, and 8 shall be honored, provided that REQ/ACK OFFSET is greater than 00h. The field val-
ues are defined in Table 14.

Table 15 shows which transfer period factors may be used with different types of transfer agreements, provided 
REQ/ACK OFFSET is greater than 00h.

Table abbreviations are defined as follows:

M =

Mandatory: Support for the indicated transfer agreement shall be implemented if the indicated transfer 
period factor is implemented.

O =

Optional: Support for the indicated transfer agreement may be implemented if the indicated transfer 
period factor is implemented.

NS = Not Supported: The indicated transfer agreement shall not be allowed if the indicated transfer factor is 

selected.

Table 20 defines valid combinations of TRANSFER PERIOD FACTOR and other fields.

00h - 06h

Reserved

N/A

N/A

07h

Transfer period equals 3.125 ns

PPR

Fast-320

08h

Transfer period equals 6.25 ns

PPR

Fast-160

09h

Transfer period equals 12.5 ns

PPR

Fast-80

0Ah

Transfer period equals 25 ns

PPR, SDTR

Fast-40

0Bh

Transfer period equals 30.3 ns

PPR, SDTR

Fast-40

0Ch

Transfer period equals 50 ns

PPR, SDTR

Fast-20

0Dh - 18h

Transfer period equals the TRANSFER PERIOD FACTOR x 4

PPR, SDTR

Fast-20

19h - 31h

Transfer period equals the TRANSFER PERIOD FACTOR x 4

PPR, SDTR

Fast-10

32h - FFh

Transfer period equals the TRANSFER PERIOD FACTOR x 4

PPR, SDTR

Fast-5

00h - 06h

Reserved

07h - 08h

NS

M

NS

M

NS

M

09h

M

NS

O

O

NS

M

0Ah

M

NS

O

O

O

O

0Bh

M

NS

O

O

O

O

0Ch

M

NS

O

O

O

O

0Dh - 18h

M

NS

O

O

O

O

19h - 31h

M

NS

O

O

O

O

32h - FFh

M

NS

O

O

O

O