Over-Voltage Or Under-Voltage Power Down; Over-Temperature Or Under-Temperature Power Down; Restart Sim900D By Pwrkey Pin - SimCom SIM900D Hardware Design

For detail about the AT command "AT+CPOWD", please refer to document [1]
4.2.2.3

Over-voltage or Under-voltage Power down

The module software monitors the VBAT voltage constantly.
If the voltage ≤ 3.3V, the following URC will be reported:
UNDER-VOLTAGE WARNNING
If the voltage ≥ 4.7V, the following URC will be reported:
OVER-VOLTAGE WARNNING
If the voltage < 3.2V, the following URC will be reported, and the module will be automatically powered down.
UNDER-VOLTAGE POWER DOWN
If the voltage > 4.8V, the following URC will be reported, and the module will be automatically powered down.
OVER-VOLTAGE POWER DOWN
At this moment, AT commands can not be executed any more, and only the RTC is still active. Power down mode
can also be indicated by STATUS pin, which is at low level at this time.
4.2.2.4

Over-temperature or Under-temperature Power down

The module will constantly monitor the temperature of the module,
If the temperature > +80℃, the following URC will be reported:
+CMTE: 1
If the temperature < -30℃, the following URC will be reported:
+CMTE:-1
If the temperature > +85℃, the following URC will be reported, and the module will be automatically powered
down.
+CMTE: 2
If the temperature < -40℃, the following URC will be reported, and the module will be automatically powered
down.
+CMTE:-2
At this moment, AT commands can not be executed any more, and only the RTC is still active. Power down mode
can also be indicated by STATUS pin, which is at low level at this time.
The AT command "AT+CMTE" could be used to read the temperature when the module is running.
For details please refer to document [1].
4.2.3

Restart SIM900D by PWRKEY Pin

When the module works normally, if the user wants to restart the module, follow the procedure below:
1) Power down the module.
2) Wait for at least 800mS after STATUS pin changed to low level.
3) Power on the module.
SIM900D_Hardware Design_V2.02
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Smart Machine Smart Decision
2012-05-07