User's Manual

GE866-DUAL Hardware User Guide
1VV0301051 Rev. 2 – 2014-04-07 7
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Reserved. Page 54 of 82
Mod. 0805 2011-07 Rev.2
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
1.8V 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 1.8V
CMOS, then it can be buffered with an open collector
transistor with a 47K pull up to 1.8V.
NOTE:
In order to avoid a back powering effect it is recommended to
avoid having any HIGH logic level signal applied to the
digital pins of the GE866-QUAD when the module is powered OFF
or during an ON/OFF transition.
TIP:
The V_AUX / PWRMON pin can be used for input pull up reference
or/and for ON monitoring.
11.3. Using a GPIO Pad as OUTPUT
The GPIO pads, when used as outputs, can drive 1.8V 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.
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.