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GE863-PRO
3
Hardware User Guide
1vv0300773a Rev. 0 - 24/01/08
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 22 of 64
A simple circuit to do it is:
NOTE: don't use any pull up resistor on the ON/OFF*-AP line, it is internally pulled up to VBATT2. Using
pull up resistor may bring to latch up problems on the GE863-PRO
3
power regulator and improper power
on/off of the module. The line ON/OFF*-AP must be connected only in open collector configuration or tied
to ground (if ARM needs to stay always on).
NOTE: In this document all the lines that are inverted, hence have active low signals are labeled with a
name that ends with a "*" or with a bar over the name.
TIP: To check if the device has powered on, the hardware line 3.1V_OUT can be monitored.
It is possible to use also the SHDN line to turn ON the device with the ARM RTC trigger by connecting
it to the ON/OFF*-AP pin through a transistor buffer.
After the Initial bootstrap, the line PC29 goes HIGH allowing the device to keep itself on;
If you need a toggle command to turn on/off the device, then you can use the line PC29 to keep the
ARM on after it’s start-up and connect the on/off button to the ON/OFF*-AP pin through a buffer
transistor while connecting it to a GPIO to sense it’s toggling (e.g. PC31) for shutting down the ARM
by lowering the PC29 pin.
TIP: To Keep the ARM ON you can use the PC29 pin that goes high right after the bootstrap
ON/OFF*-AP #
Power ON/OFF
GND
R1
R2
Q1