Power Down Module Using At Command; Over-Voltage Or Under-Voltage Automatic Shutdown - Quectel M85 Hardware Design

The power down procedure causes the module to log off from the network and allows the firmware to
save important data before completely disconnecting the power supply.
Before the completion of the power down procedure, the module sends out the result code shown below:
NORMAL POWER DOWN
NOTE
This result code does not appear when autobauding is active and DTE and DCE are not correctly
synchronized after start-up. The module is recommended to set a fixed baud rate.
After that moment, no further AT commands can be executed. Then the module enters the power down
mode, only the RTC is still active. The power down mode can also be indicated by the STATUS pin, which
is a low level voltage in this mode.

3.4.2.2. Power Down Module Using AT Command

It is also a safe way to turn off the module via AT command ―AT+QPOWD=1‖. This command will let the
module to log off from the network and allow the firmware to save important data before completely
disconnecting the power supply.
Before the completion of the power down procedure the module sends out the result code shown below:
NORMAL POWER DOWN
After that moment, no further AT commands 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 STATUS pin,
which is a low level voltage in this mode.
Please refer to the document [1] for details about the AT command ―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 is ≤ 3.5V, the
following URC will be presented:
UNDER_VOLTAGE WARNING
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