NXP Semiconductors OM13260, Руководство по установке, Страница: 47 / 71

NXP Semiconductors
UMxxxxx
Install Guide
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Preliminary 1
— September 6, 2013
© NXP B.V. 2013. All rights reserved.
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6. GPIO Target Board (OM13303)
The GPIO Target Board (OM13303) is used to monitor the Input/Output (IO) signals from a GPIO. The
board has eight channels, each with a push switch and an LED indicator. See figure 6.1
6.1 Theory of Operation
Each of the eight channels operates independently and in the same way. The voltage applied to the
input pin is compared in a windows comparator, which in turn drives a dual color LED. The thresholds
for the comparators are set to one-third (logic zero) and two-thirds (logic one) of the supply voltage.
These values correspond to the I2C logic threshold voltages for the I2C specification.
When a push button is pressed a logic zero is applied the channel, which can be read by the GPIO
device to which the GPIO Target Board is attached. A two by five header is used to connect to the Fm+
Development Board (OM13260) or a GPIO Daughter Card, with a flat ribbon cable (supplied in the kit).
Two connectors are installed, one on each end of the board, and on opposite sides of the PCB to aid in
connection without the cables blocking the buttons or LEDs.
There are no option jumpers and no adjustments on the GPIO Target Board (OM13303).
Fig 6.1 OM13303 GPIO Target Board PCB Assembly (front side)
Unlike other PCB assemblies in the Fm+ Development Kit (OM13320) the GPIO Target Board
(OM13303) has components on both sides of the PCB. See figure 6.2
Fig 6.2 OM13303 GPIO Target Board PCB Assembly (back side)