Seagate ST32430N Product Manual - Page 60

Product Manual - Hawk 2LP Family SCSI-2 Volume 1, Rev. A, 6.4.3, Terminator requirements, Note., 6.4

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52 Product Manual - Hawk 2LP Family SCSI-2 (Volume 1), Rev. A 11.6.4.3 Terminator requirements Internal disc drive I/O termination (provided only in single ended I/O model drives) consists of active circuits in an LSI module that is permanently mounted on the PCB. All single initiator/single target (nondaisychain) applications require that the Initiator and disc drive be terminated. Daisychain applications require that only the units at each end of the daisy-chain be terminated. All other peripherals on the chain must not be terminated. (See Figure 11.6.3-2). Note. Remove drive terminator enabling jumper TE (see Figure 10.1-1) where terminators are not required. Removal of terminator power source selection jumper TP (see Figure 10.1-1) does not disconnect the terminator resistors from the circuit. It is highly recommended that ANSI SCSI-2 Standard's Alternative 2 termination (active termination) be used for applications with single-ended ("N" models), especially if the bus will be operated at transfer rates above 5 Mbytes/sec. The "N" model provides on-board active termination that can be disabled by removal of the enable jumper TE (see Figure 10.1-1). Note. ACTIVE TERMINATORS ARE HIGHLY RECOMMENDED FOR USE IN THE DAISYCHAIN AS DESCRIBED ABOVE. ACTIVE AND PASSIVE TERMINATORS SHOULD NOT BE MIXED ON THE SAME SCSI BUS. Differential I/O "ND" models do not have terminators on the PCB. The user, systems integrator or host equipment manufacturer must provide a terminator arrangement external to the drive. 11.6.4.4 Terminator power The drive may be configured to accept terminator power from pin 26 of the SCSI Bus, to supply power to the SCSI bus or to provide terminator power for internal termination circuits from the drive power connector. See Figures 10.1-1 and 11.6-1. The drive can provide power both to its own terminators and to the SCSI Bus terminator power line (Pin 26) if both "TP" jumpers are on. SCSI devices providing terminator power (TERMPWR)* shall have the following characteristics: V TERM = 4.50 V to 5.25 V 800 mA min source drive capability 1.0 A maximum *See Figure 10.1-1 for configuration details.

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52
Product Manual - Hawk 2LP Family SCSI-2 (Volume 1), Rev. A
______________________________________________________________________________________
11.6.4.3
Terminator requirements
Internal disc drive I/O termination (provided only in single ended I/O model drives)
consists of active circuits
in an LSI module that is permanently mounted on the PCB. All single initiator/single target (nondaisychain)
applications require that the Initiator and disc drive be terminated. Daisychain applications require that only the
units at each end of the daisy-chain be terminated. All other peripherals on the chain must not be terminated.
(See Figure 11.6.3-2).
Note.
Remove drive terminator enabling jumper
TE
(see Figure 10.1-1) where terminators are not required.
Removal of terminator power source selection
jumper
TP
(see Figure 10.1-1) does not disconnect
the terminator resistors from the circuit.
It is highly recommended that ANSI SCSI-2 Standard's Alternative 2 termination (active termination) be used
for applications with single-ended ("N" models), especially if the bus will be operated at transfer rates above
5 Mbytes/sec. The "N" model provides on-board active termination that can be disabled by removal of the
enable jumper
TE
(see Figure 10.1-1).
Note.
ACTIVE TERMINATORS ARE HIGHLY RECOMMENDED FOR USE IN THE DAISYCHAIN AS
DESCRIBED ABOVE. ACTIVE AND PASSIVE TERMINATORS SHOULD NOT BE MIXED ON THE
SAME SCSI BUS.
Differential I/O "ND" models do not have terminators on the PCB. The user, systems integrator or host
equipment manufacturer must provide a terminator arrangement external to the drive.
11.6.4.4
Terminator power
The drive may be configured to accept terminator power from pin 26 of the SCSI Bus, to supply power to the
SCSI bus or to provide terminator power for internal termination circuits from the drive power connector. See
Figures 10.1-1 and 11.6-1. The drive can provide power both to its own terminators and to the SCSI Bus
terminator power line (Pin 26) if both "
TP
" jumpers are on.
SCSI devices providing terminator power (TERMPWR)* shall have the following characteristics:
V TERM = 4.50 V to 5.25 V
800 mA min source drive capability
1.0 A maximum
*See Figure 10.1-1 for configuration details.