Synchronous Data Transfer; Synchronous Data Transfer Periods Supported; Req/Ack Offset; Physical Interface - Seagate ST34572N Product Manual

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9.5

Synchronous data transfer

9.5.1

Synchronous data transfer periods supported

Table 11 and Section 9.5.2 list Synchronous Data transfer periods supported by the drive. The data transfer
period to be used by the drive and the initiator is established by an exchange of messages during the Message
Phase of operation. See the section on message protocol in the SCSI Interface Product Manual , part number
77738479.
Table 11: Synchronous data transfer periods for drive
Transfer period
M (decimal)
(M times 4 nanoseconds)
12 [1]
15 [1]
18 [1]
25 100
31 125
37 150
50 200
62 250
75 300
87 350
100 400
Note.
[1] FAST-20 SCSI transfer periods.
9.5.2

REQ/ACK offset

The maximum value supported by the Barracuda 4XL family drives for REQ/ACK offset is 15 (0Fh).
9.6

Physical interface

Figure 15 shows the locations of the drive physical interface components for the N drives. Shown are the loca-
tions of the DC power connector, the SCSI interface connector, the I/O line terminators, and the drive select
and option select headers.
Details of the physical, electrical and logical characteristics are given in sections following, while the SCSI
operational aspects of Seagate drive interfaces are given in the Seagate SCSI Interface Product Manual , part
number 77738479.
This section describes the connectors, cables, signals, terminators and bus timing of the DC and SCSI I/O
interface. See Section 9.8 and Section 9.9 for additional terminator information.
9.6.1

DC cable and connector

"N" and "W" model drives receive DC power through a 4 pin connector (see Figures 15 and 16 for pin assign-
ments) mounted at the rear of the main PCB. Recommended part numbers of the mating connector are listed
below, but equivalent parts may be used.
Type of cable Connector
14 AWG MP 1-480424-0
"WC" and "DC" model drives receive power through the 80 pin I/O connector. See Tables 16 and 17.
50 [1]
62.5 [1]
75 [1]
Contacts (20-14 AWG)
AMP 60619-4 (Loose Piece)
AMP 61117-4 (Strip)
Barracuda 4XL Product Manual, Rev. B