GE/GC864-QUAD V2 and GE864-GPS Hardware User Guide
1vv0300915 Rev.5 – 2011-10-03
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved.
Page 68 of 94
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.
11.5.
Using the RFTXMON Output GPIO5
The GPIO5 pin, when configured as RFTXMON Output, is controlled by the GE/GC 864
QUAD V2 module and will rise when the transmitter is active and fall after the transmitter
activity is completed.
There are 2 different modes for this function:
1)
Active during all the calls:
For example, if a call is started, the line will be HIGH during all the conversation and it will
be again LOW after hanged up.
The line rises up 300ms before first TX burst and will became again LOW from 500ms to 1s
after last TX burst.
2)
Active during all the TX activity:
The GPIO is following the TX bursts
Please refer to the AT User interface manual for additional information on how to enable this
function.
11.6.
Using the Alarm Output GPIO6
The GPIO6 pad, when configured as Alarm Output, is controlled by the module and will rise
when the alarm starts and fall after the issue of a dedicated AT command.
