User Guide

GE9
GE9GE9
GE910 Hardware User Guide
10 Hardware User Guide10 Hardware User Guide
10 Hardware User Guide
1vv0300962 Rev.4 2012-06-25
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 23 of 73
Mod. 0805 2011-07 Rev.2
4.3. HW Unconditional Shutdown on GE910
4.3.1. Hardware Unconditional shutdown
WARNING:
The hardware unconditional Shutdown must not be used during normal operation of the device
since it does not detach the device from the network. It shall be kept as an emergency exit
procedure to be done in the rare case that the device gets stacked waiting for some network or
SIM responses.
To unconditionally Shutdown the GE910, the pad HW_SHUTDOWN* must be tied low for at
least 200 milliseconds and then released. After this operation the module is in OFF condition.
The maximum current that can be drained from the HW_SHUTDOWN* pad is 0,4 mA.
NOTE:
Do not use any pull up resistor on the HW_SHUTDOWN* line or any totem pole digital output.
Using pull up resistor may bring to latch up problems on the GE910 power regulator and
improper functioning of the module. The line HW_SHUTDOWN* must be connected only in
open collector configuration.
TIP:
The unconditional hardware shutdown must always be implemented on the boards and the
software must use it as an emergency exit procedure.
A simple circuit to do it is: