M12 Hardware Design
M12_Hardware_Design_V3.3
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Before the completion of the power-down procedure, the module sends out the result code as
shown below:
NORMAL POWER DOWN
After this moment, no other 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.
For details about the AT command of “AT+QPOWD”, please refer to
document [1]
.
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
If the voltage is ≥ 4.5V, the following URC will be presented:
OVER_VOLTAGE WARNING
The normal input voltage range is from 3.3V to 4.6V. If the voltage is > 4.6V or <3.3V, the module
would automatically shutdown itself.
If the voltage is <3.3V, the following URC will be presented:
UNDER_VOLTAGE POWER DOWN
If the voltage is >4.6V, the following URC will be presented:
OVER_VOLTAGE POWER DOWN
Note: These result codes do not appear when autobauding is active and DTE and DCE are not
correctly synchronized after start-up. The module is recommended to set to a fixed baud rate.
After this moment, no other AT command can be executed, the module logs off network and enters
POWER DOWN mode, and only RTC is still active. The POWER DOWN mode can also be
indicated by the pin STATUS, which is a low level voltage in this mode.
3.4.2.4. Emergency shutdown
The module can be shut down by driving the pin EMERG_OFF to a low level voltage for over 20ms
and then releasing it. The EMERG_OFF pin can be driven by an Open Drain/Collector driver or a
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