Synchronous Data Transfer; Synchronous Data Transfer Periods Supported; Req/Ack Offset; Physical Interface - Seagate ST336704LW Product Manual

Cheetah 36LP Product Manual, Rev. B
9.5

Synchronous data transfer

9.5.1

Synchronous data transfer periods supported

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 75789509. In the following tables, M is the synchronous period value (in the transfer rate
negotiation message) that represents the associated transfer period and transfer rate values.
Table 10 lists the synchronous data transfer periods supported by the drive in DT Data phase. DT Data phase
is only allowed when using the LVD interface.
Table 10: Synchronous DT
Transfer period
M (decimal)
(nanoseconds)
9 12.5
10 25
12 50
25 100
Table 11 lists the synchronous data transfer periods supported by the drive in ST Data phase. ST Data phase
is allowed with either LVD or SE interface except as noted.
Table 11: Synchronous ST Data transfer periods
Transfer period
M (decimal)
(nanoseconds)
10 25
12 50
25 100
50 200
1. This transfer rate is only allowed when using the LVD interface.
9.5.2

REQ/ACK offset

The maximum value supported by the Cheetah 36LP family drives for REQ/ACK offset is 63 (3Fh).
9.6

Physical interface

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.
Figures 15 and 16 show the locations of the DC power connector, SCSI interface connector, drive select head-
ers, 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 SCSI Interface Product Manual, part number
75789509.
9.6.1

DC cable and connector

ST336704LW/LWV drives receive DC power through a 4 pin connector (see Figure 17 for pin assignment)
mounted at the rear of the main PCBA. 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
Data
transfer periods
Transfer rate
(megatransfers/second)
80.0
40.0
20.0
10.0
Transfer rate
(megatransfers/second)
1
40.0
20.0
10.0
5.0
Contacts (20-14 AWG)
AMP 60619-4 (Loose Piece)
AMP 61117-4 (Strip)
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