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This application note describes three methods of setting the SCSI ID (or device address) of the Gypsy-2000. The three suggestions are for the users who purchase the Gypsy-2000 printed circuit assembly without the enclosure.
When the Gypsy-2000 is supplied in an enclosure the SCSI ID selection is provided for by means of a push wheel switch mounted on the panel.
When the Gypsy printed circuit assembly is purchased without the enclosure, the user may wish to mount the printed circuit assembly in a user provided enclosure and use a push wheel switch connected by cable to the printed circuit assembly. Two alternatives include mounting a DIP switch on the PC board or mounting a 2x4 header on the PC board (using shorting plugs to determine the SCSI ID).
The following descriptions refer to JP2 and S2. These are through hole patterns on the Gypsy printed circuit board. They are located adjacent to the SCSI connector.
S2 refers to eight through holes arranged in an 8-pin DIP (Dual In-line Package) pattern. This hole pattern is intended for the mounting of a 4 section, 8 pin DIP switch.
JP2 refers to four through holes arranged in a line between the two rows of holes which constitute the S2 pattern. This hole pattern is intended for the mounting of a 1x4 header.
Remember that the SCSI ID setting may be changed while the Gypsy is powered on but that the Gypsy must be reset (or power cycled off then back on) for the new setting to take effect.
The following is suggested when the device address push wheel switch is mounted on an enclosure panel.
A 1x4 header is mounted at position JP2. This header will accept a cable from a Cherry(tm) T55-07 push wheel 8 position switch. The table below shows which switch contacts are open or closed for each of the 8 IDs. The table also shows the wiring from JP2 to the switch.
SCSI ID (Device Address)
JP2 SW 0 1 2 3 4 5 6 7
=== === =====================================================
-1 -C
-2 -4 open open open open closed closed closed closed
-3 -2 open open closed closed open open closed closed
-4 -1 open closed open closed open closed open closed
N.C. -8
A four section, 8 pin DIP switch can be mounted directly to the Gypsy PC board at the 8 pin DIP pattern, S2. Sections 2, 3, and 4 are used to select the SCSI ID. The function of section 1 is not defined.
The table below shows which switch sections are open or closed for each of the 8 IDs. The table also shows which pins are associated with each switch section.
DIP SW S2 SCSI ID (Device Address)
Section Pins 0 1 2 3 4 5 6 7
======= ====== =====================================================
1 -1, -8
2 -2, -7 open open open open closed closed closed closed
3 -3, -6 open open closed closed open open closed closed
4 -4, -5 open closed open closed open closed open closed
A 2x4 header can be mounted in the position occupied by JP2 and the first 4 pins of S2. Shorting bars can then be placed over the second, third, and fourth pairs of pins to determine the SCSI ID. Note that S2-1, JP2-1, -2, -3, and -4 are all common and that shorting bars can be stored on them.
SCSI ID (Device Address)
JP2 S2 0 1 2 3 4 5 6 7
=== === =====================================================
-2 -2 open open open open short short short short
-3 -3 open open short short open open short short
-4 -4 open short open short open short open short
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