User's Manual

LE940B6 Hardware User Guide

1VV0301331 Rev. 1.8 - 2017-03-15

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5. Hardware Commands

5.1. Turning on the LE940B6 Module

To turn on the LE940B6 module, the ON_OFF_N pad must be asserted low in the range of 80 - 120

milliseconds and then released.

Figure 3 illustrates a simple circuit to power on the module using an inverted buffer output.

Figure 3: Power-on Circuit

GND

Power ON Impulse

80ms < Hold Time < 120ms

ON_OFF_N

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."

5.2. Initialization and Activation State

After turning on the LE940B6 module, a predefined internal boot sequence performs the HW and

SW initialization of the module, which takes some time to fully complete. During this process, the

LE940B6 is not accessible.

As shown in Figure 4, the LE940B6 becomes operational at least 25 seconds after PWRMON goes

HIGH.

NOTE:

During the Initialization state, AT commands are not available. The DTE host must wait for the

Activation state prior to communicating with the LE940B6.