Product manual

Product Manual - Hawk 2 Family (Wide bus) SCSI-2 (Volume 1), Rev. A 39
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SSP Used only as a cable connection for the reference index signal (REFIND+) (J1-6A and J6
Pin 6, bottom) for sync spindle feature. J1-10A or J6-10 provides ground. See paragraphs
10.2, 5.7 for description of synchronized spindle operation. When no cable is connected, no
jumpers should be installed. Factory default is no jumper installed. If a jumper is installed
between pins 5 and 6 it will erroneously enable Drive ID bit A2.
BUSY LED See Note [4]
10.2 Synchronized spindles interface
The Synchronized Spindles Interface (SSI) allows several drives operating from the same host to operate
their spindles at a synchronized rotational rate. Details of the electrical and physical interfaces follow in
paragraphs 10.2.1 and 10.2.1.2 and 10.2.1.3. The system operation is described in paragraph 5.7. Spindle
synchronization typically works effectively only if all drives connected to the REFIND+ signal are identical in
make and model.
10.2.1 Electrical description
The electrical interface consists of one digital TTL reference index signal and ground. The reference index
signal (REFIND+) is an output if the drive is configured as a master and is an input otherwise. The reference
index signal is connected from drive to drive in a daisychain fashion as shown in Figure 5.7-1.
10.2.1.1 Drivers and receivers
Figure 10.2.1-1 shows a diagram of the driver/receiver circuit. The driver circuits have the following electrical
specifications.
Negated (False): 0.0 V to +0.4 V @I = - 48 mA (max)
Asserted (True): +2.24 V to +5.25V@I = +250 µA
[1] This connection exists only on the ST12400WC model.
[2] See paragraph 10.2.1.2
Figure 10.2.1-1. SCSI reference index signal driver/receiver combination
Driver Receiver
2K Ohm [2]
REFIND +
GND
Main PCB
J1-37 [1]
J6-6 or J1-6A
J6-10 or J1-10A
J1-47 [1]
+5V