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There are 7812, 7805 and LM317 linear regulator ICs on the power supply to generate
+5V, -5V, +12V, -12V and +3.3V for the device. On the standby mode just +12Vst and +5V
supplies are generating for standby power consumption.
The ES6008/18 requires 2.5V to operate. This voltage is generated from +5V.
13 C
ONNECTORS
13.1 ATAPI D
S
RIVE
The I/O connector is a 40-pin connector as shown in figure A.1, with pin assignments as shown in table
A.1. The connector shall be keyed to prevent the possibility of installing it upside down. A key is provided
by the removal of pin 20. The corresponding pin on the cable connector shall be plugged.
The cable plug, not the receptacle, governs the pin locations. The way in which the receptacle is mounted
on the printed circuit board affects the pin positions, and pin 1 shall remain in the same relative position.
This means the pin numbers of the receptacle may not reflect the conductor number of the plug. The
header receptacle is not polarized, and all the signals are relative to pin 20, which is keyed.
By using the plug positions as primary, a straight cable can connect devices. As shown in figure A.1,
conductor 1 on pin 1 of the plug shall be in the same relative position no matter what the receptacle
numbering looks like. If receptacle numbering was followed, the cable would have to twist 180 degrees
between a device with top-mounted receptacles, and a device with bottom-mounted receptacles.
40
Circuit board
C
TANDARD
ONNECTOR
1
20
2
Figure A.1 - 40-pin connector mounting
16
Circuit board
40
20
1
2
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