User's Manual

CE910 Family Hardware User Guide
1vv0301010 Rev.11 – 2015-10-27
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
Page 28 of 75
4.4. Hardware Unconditional Shutdown
The Unconditional shutdown of the module could be activated using the HW_SHUTDOWN*
line(pad R13).
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 used as an emergency exit procedure.
To unconditionally shutdown the CE910, the pad HW_SHUTDOWN* must be tied low for at least
800 milliseconds and then released.
NOTE:
Do not use any pull up resistor on the HW_SHUTDOWN* line nor any totem pole digital output. It is
pulled up internally to VBATT with 57kΩ. Using an external pull up resistor may bring latch up
problems on the CE910 power regulator and improper functioning of the module.
The line HW_SHUTDOWN* must be connected only in open collector configuration.
The HW_SHUTDOWN* will generate an unconditional shutdown of the module without an
automatic restart.
The module will shutdown but will NOT perform the detach from the cellular network.
To proper power on again the module please refer to 4.1 Turning ON the CE910.
TIP:
The unconditional hardware shutdown must always be implemented on the boards and the software
must use it only as an emergency exit procedure.
A simple circuit to unconditionally shutdown the module is illustrated below: