Seagate ST15150N Product Manual - Page 79

Physical characteristics

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ST15150N/ND/W/WD/WC/DC Product Manual, Rev. D 69 11.7.1 Physical characteristics This section defines the connectors, cables, signals, terminators, and bus timing needed to implement the SCSI interface. 11.7.1.1 Physical description You can daisy chain multiple SCSI devices on a common cable if each device has the same types of drivers and receivers (all single-ended or all differential). Devices having single-ended interface circuits cannot be on the same daisy chain with devices having a differential interface circuit. Both ends of the cable must be terminated. All signals are common between SCSI devices. A maximum of 8 SCSI devices (including the host) may be daisy chained together on non-wide systems (ST15150N/ND). Wide SCSI systems (ST15150W/WD/WC/DC) can have a maximum of 16 SCSI devices (including the host) daisy chained together. Terminate both ends of the daisy chain, but do not terminate any intermediate SCSI device. Refer to Section 11.7.3.3 for information about how to terminate each model. 11.7.1.2 Cable requirements Sections 11.7.1.2.1, 11.7.1.2.2, and 11.7.1.2.3 describe the single-ended, differential, and general cable requirements for Barracuda 4 drives. 11.7.1.2.1 Single-ended I/O circuits The maximum total cable length for use with drives having single-ended I/O driver and receiver circuits is 6 meters (19.7 feet) when operating at line data transfer rates of 5 Mbytes/second or less, and 3 meters (9.85 feet) when operating at transfer rates greater than 5 Mbytes/second (fast SCSI). A stub length of no more than 0.1 meter (0.33 foot) is allowed off the mainline interconnection with any connected equipment. An ideal impedance match with cable terminators implies a cable characteristic impedance of 132 ohms. Single-ended I/O cable pin assignments for ST15150N drives are shown in Table 14. Single-ended I/O cable pin assignments for ST15150W drives are shown in Table 16. Single-ended I/O cable pin assignments for ST15150WC drives are shown in Table 18. 11.7.1.2.2 Differential I/O circuits The maximum total cable length for use with drives having differential I/O drivers and receiver circuits is 25 meters (82 feet). A stub length of no more than 0.2 meter (0.66 foot) is allowed off the mainline interconnection with any connected equipment. An ideal impedance match with cable terminators implies a cable characteristic impedance of 122 ohms. Differential I/O pin assignments for ST15150ND drives are shown in Table 15. Differential I/O pin assignments for ST15150WD drives are shown in Table 17. Differential I/O pin assignments for ST15150DC drives are shown in Table 19.

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ST15150N/ND/W/WD/WC/DC Product Manual, Rev. D
69
11.7.1
Physical characteristics
This section defines the connectors, cables, signals, terminators, and bus
timing needed to implement the SCSI interface.
11.7.1.1
Physical description
You can daisy chain multiple SCSI devices on a common cable if each device
has the same types of drivers and receivers (all single-ended or all differen-
tial). Devices having single-ended interface circuits cannot be on the same
daisy chain with devices having a differential interface circuit. Both ends of
the cable must be terminated. All signals are common between SCSI
devices. A maximum of 8 SCSI devices (including the host) may be daisy
chained together on non-wide systems (ST15150N/ND). Wide SCSI sys-
tems (ST15150W/WD/WC/DC) can have a maximum of 16 SCSI devices
(including the host) daisy chained together.
Terminate both ends of the daisy chain, but do not terminate
any intermedi-
ate SCSI device. Refer to Section 11.7.3.3 for information about how to
terminate each model.
11.7.1.2
Cable requirements
Sections 11.7.1.2.1, 11.7.1.2.2, and 11.7.1.2.3 describe the single-ended,
differential, and general cable requirements for Barracuda 4 drives.
11.7.1.2.1
Single-ended I/O circuits
The maximum total cable length for use with drives having single-ended I/O
driver and receiver circuits is 6 meters (19.7 feet) when operating at line data
transfer rates of 5 Mbytes/second or less, and 3 meters (9.85 feet) when
operating at transfer rates greater than 5 Mbytes/second (fast SCSI). A stub
length of no more than 0.1 meter (0.33 foot) is allowed off the mainline
interconnection with any connected equipment. An ideal impedance match
with cable terminators implies a cable characteristic impedance of 132 ohms.
Single-ended I/O cable pin assignments for ST15150N drives are shown in
Table 14. Single-ended I/O cable pin assignments for ST15150W drives are
shown in Table 16. Single-ended I/O cable pin assignments for ST15150WC
drives are shown in Table 18.
11.7.1.2.2
Differential I/O circuits
The maximum total cable length for use with drives having differential I/O
drivers and receiver circuits is 25 meters (82 feet). A stub length of no more
than 0.2 meter (0.66 foot) is allowed off the mainline interconnection with any
connected equipment. An ideal impedance match with cable terminators
implies a cable characteristic impedance of 122 ohms. Differential I/O pin
assignments for ST15150ND drives are shown in Table 15. Differential
I/O pin assignments for ST15150WD drives are shown in Table 17.
Differential I/O pin assignments for ST15150DC drives are shown in
Table 19.