Smart Machine Smart Decision
SIM808_Hardware Design_V1.00 2014.03.27
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4.3.1
Function Mode
There are three functionality modes, which could be set by the AT command “AT+CFUN=<fun>”. The command
provides the choice of the functionality levels <fun>=0, 1, 4.
z
AT+CFUN=0: minimum functionality.
z
AT+CFUN=1: full functionality (default).
z
AT+CFUN=4: flight mode (disable RF function).
Table 8: The current consumption of function modes (BS-PA-MFRMS=5)
<Fun>
Current consumption(uA) (CSCLK=1)
0
869.5
1
1400
4
922.5
Minimum functionality mode minimizes the current consumption to the lowest level. If SIM808 is set to
minimum functionality by “AT+CFUN=0”, the RF function and SIM card function will be disabled. In this case,
the serial port is still accessible, but all AT commands correlative with RF function and SIM card function will not
be accessible.
For detailed information about the AT Command “AT+CFUN=<fun>”, please refer to
document [1]
.
4.3.2
Sleep Mode (AT+CSCLK=1)
When the GPS function is shut off, user can control SIM808 module to enter or exit the sleep mode
(AT+CSCLK=1) by DTR signal. When DTR is in high level and without interrupt (on air and hardware such as
GPIO interrupt or data in serial port), SIM808 will enter sleep mode automatically. In this mode, SIM808 can still
receive paging or SMS from network but the serial port is not accessible.
Note: For SIM808, it requests to set AT command “AT+CSCLK=1” and ensure DTR at high level to enable the sleep mode ; the
default value is 0, which can not make the module to enter sleep mode. For more details please refer to document [1].
4.3.3
Wake Up SIM808 from Sleep Mode (AT+CSCLK=1)
When SIM808 is in sleep mode (AT+CSCLK=1), the following methods can wake up the module:
z
Pull down DTR pin.
The serial port will be active after DTR pin is pulled to low level for about 50ms.
z
Receive a voice or data call from network.
z
Receive a SMS from network.
z
Receive external interrupt
z
Charge VBUS pin
