SIM5218E Hardware Design
SIM5218E_ Hardware Design_V1.06
2012.09.21
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3.4.2.3 Under-voltage automatic warning
Software will constantly monitor the voltage applied on the VBAT, if the measured battery voltage
is no more than 3.4V, the following URC will be presented:
warning! voltage is low : 3.3v
Note:
Under-voltage automatic warning function default is disabled. One can enable it by
AT+CVALARM.
3.4.2.4 Under-voltage automatic shutdown
Besides the Under-voltage automatic warning, system will monitor the working voltage and power
off the module if the voltage is lower to a specified value which can be set by AT+CPMVT in
order to protect the module.
Note: this feature default is disabled, One can use AT+CPMVT to active it.
At this moment, no more AT commands can be executed. The module will be logged off from
the network and enters POWER DOWN mode, only the RTC is still active (if backup battery is
connected to VRTC pin).
3.5 Power saving
There are two methods to achieve SIM5218E module extreme low power. “AT+CFUN” is used to
set module into minimum functionality mode and GPIO4 hardware interface signal can be used to
set system to be Flight mode (Close RF).
3.5.1 Minimum functionality mode
Minimum functionality mode reduces the functionality of the module to a minimum and, thus,
minimizes the current consumption to the lowest level. This mode is set with the “AT+CFUN”
command which provides the choice of the functionality levels <fun>=0
，
1
，
4
z
0: minimum functionality;
z
1: full functionality (Default);
z
4: disable both transmit and receive RF circuits of the phone ;
If SIM5218E has been set to minimum functionality by “AT+CFUN”, then the RF function and
SIM card function will be closed, in this case, the serial port is still accessible, but all AT
commands need RF function or SIM card function will not be accessible.
If SIM5218E has disabled all RF function by “AT+CFUN”, then RF function will be closed, the
serial port is still active in this case but all AT commands need RF function will not be accessible.
When SIM5218E is in minimum functionality or has disabled all RF functionality by
