Quectel M20 Hardware Design page 31

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M20 Hardware Design

PWRKEY

（INPUT）

VDD_EXT

（OUTPUT）

3.4.2.2 Turn off module using AT command

Customer's application can use an AT command "AT+QPOWD=1" to turn off the module. This

command will let the module to log off from the network and allow the software to save important

data before completely disconnecting the power supply, thus it is a safe way.

Before the completion of the power-down procedure the module sends out the result code shown

below:

NORMAL POWER DOWN

After this moment, no further AT command can be executed. And then the module enters the

POWER DOWN mode, only the RTC is still active. The POWER DOWN mode can also be

indicated by VDD_EXT pin, which is a low level voltage in this mode.

Please refer to document [1] for detail about the AT command of "AT+QPOWD".

3.4.2.3 Over-voltage or under-voltage automatic shutdown

The module will constantly monitor the voltage applied on the VBAT, if the voltage ≤ 3.5V, the

following URC will be presented:

UNDER-VOLTAGE WARNNING

If the voltage ≥ 4.5V, the following URC will be presented:

OVER-VOLTAGE WARNNING

The uncritical voltage range is 3.4V to 4.6V. If the voltage ≥ 4.6V or ≤ 3.4V, the module would

automatically shutdown itself.

M20_HD_V1.01

1s > Pulldown > 0.6s

>0.7*VBAT

<0.3*VBAT

Figure 8: Timing of turn off the module

Logout net about 2s to 8s

Hiz

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