User's Manual

GE/GC864-QUAD V2 and GE864-GPS Hardware User Guide

1vv0300915 Rev.2 – 2011-06-15

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Reserved. Page 73 of 97

11.2. Using a GPIO Pad as INPUT

The GPIO pads, when used as inputs, can be connected to a

digital output of another device and report its status,

provided this device has interface levels compatible with the

2.8V CMOS levels of the GPIO.

If the digital output of the device to be connected with the

GPIO input pad has interface levels different from the 2.8V

CMOS, then it can be buffered with an open collector

transistor with a 47K pull up to 2.8V, this pull up must be

switched off when the module is in off condition.

11.3. Using a GPIO Pad as OUTPUT

The GPIO pads, when used as outputs, can drive 2.8V CMOS

digital devices or compatible hardware. When set as outputs,

the pads have a push-pull output and therefore the pull-up

resistor may be omitted.

The illustration below shows the base circuit of a push-pull

stage:

11.4. Using the RF Transmission Control GPIO4

The GPIO4 pin, when configured as RF Transmission Control

Input, permits to disable the Transmitter when the GPIO is set

to Low by the application.

In the design is necessary to add a resistor 47K pull up to

2.8V, this pull up must be switched off when the module is in

off condition.

VDD

GPIO7