SIM Tech SIMCom SIM800, Проектирование аппаратного обеспечения

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SIM800_Hardware Design_V1.09 24 2016-06-30
PWRKEY
VDD_EXT
STATUS
1.5s<t<33s
VIL<0.7V
Serial port
Active
Undefined
(input)
t>3s
Figure 13: Timing of Power off SIM800 by PWRKEY
Note: When module is powered off by pulling down PWRKEY, the pull down time exceeds 33 seconds will
course the module power up.
This procedure makes the module log off from the network and allows the software to enter into a secure state to
save data before completely shut down.
Before the completion of the power off procedure, the module will send URC:
NORMAL POWER DOWN
At this moment, AT commands can not be executed any more, and only the RTC is still active. Power off mode
can also be indicated by STATUS pin, which is low level at this time.
4.2.2.2. Power off SIM800 by AT Command
SIM800 can be powered down by AT command “AT+CPOWD=1”. This procedure makes the module log off from
the network and allows the software to enter into a secure state to save data before completely shut down.
Before the completion of the power off procedure, the module will send URC:
NORMAL POWER DOWN
At this moment, AT commands can not be executed any more, and only the RTC is still active. Power off mode
can also be indicated by STATUS pin, which is at low level at this time.
For details about the AT command “AT+CPOWD”, please refer to
document [1]
4.2.2.3. Over-voltage or Under-voltage Power off
The module software monitors the VBAT voltage constantly.
If the voltage ≤ 3.49V, the following URC will be reported:
UNDER-VOLTAGE WARNNING
If the voltage ≥ 4.3V, the following URC will be reported:
OVER-VOLTAGE WARNNING
If the voltage < 3.39V, the following URC will be reported, and the module will be automatically powered off.
UNDER-VOLTAGE POWER DOWN
If the voltage > 4.4V, the following URC will be reported, and the module will be automatically powered off.
OVER-VOLTAGE POWER DOWN