User's Manual

LE940B6 Hardware User Guide

1VV0301331 Rev. 1.8 - 2017-03-15

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5.3. Turning off the LE940B6 Module

Turning off the device can be done in four different ways:

• Shutdown by software command using AT#SHDN command

• Hardware shutdown using ON_OFF_N pad

• Hardware Unconditional Reset using the RESET_N pad

• Hardware Unconditional Shutdown using the SHDN_N pad

When the device is shut down by a software command or a hardware shutdown, it issues a

detach request to the network, informing the network that the device will not be reachable any

more.

NOTE:

To check if the device has powered off, monitor the VAUX/PWRMON hardware line. When

VAUX/PWRMON goes low, this indicates that the device has powered off.

NOTE:

To avoid a back-powering effect, it is recommended to avoid having any HIGH logic level signal

applied to the digital pins of the module when it is powered OFF or during an ON/OFF transition.

NOTE:

VBATT must be never removed before the proper OFF procedure is performed.

NOTE:

In case VBATT need to be removed and applied again. The application must take into account the

decay time of the power supply after removal of VBATT. VBATT input must be at zero volt prior

to the reapplication of VBATT.”

5.3.1. Shutdown by Software Command

The LE940B6 module can be shut down by a software command.

When a shutdown command is sent, LE940B6 goes into the Finalization state and at the end of

the finalization process shuts down VAUX/PWRMON.

The duration of the Finalization state can differ according to the current situation of the module,

so a value cannot be defined.

Usually, it will take more than 6 seconds from sending a shutdown command until reaching a

complete shutdown. The DTE host should monitor the status of VAUX/PWRMON to observe the

actual power-off.