SIM340 Hardware Design
Via RTC interrupt: starts ALARM modes
(please refer to chapter 3.4.1.2)
Note: The AT command must be set after the SIM340 is power on and Unsolicited Result Code
“RDY” is received from the serial port. However, if the SIM340 was set autobauding, the serial
port will received nothing, the AT command can be set after 2-3s from the SIM340 is power on.
You can use AT+IPR=x;&W to set a fix baud rate and save the configuration to non-volatile
flash memory. After the configuration was saved as fix baud rate, the Code “RDY” should be
received from the serial port all the time that the SIM340 was power on. Please refer to the
chapter AT+IPR in document [1].
3.4.2 Turn on SIM340 using the PWRKEY pin (Power on)
You can turn on the SIM340 by driving the PWRKEY to a low level voltage for some time and
then released. This pin is pulled up to VBAT in the module. The maximum current that can be
drained from the PWRKEY pin is 0.4mA. The simple circuit illustrates as the following figures.
4.7K
47K
Turn on impulse
PWRKEY
Figure 7: Turn on SIM340 using driving circuit
S1
PWRKEY
TVS1
Figure
8
: Turn on SIM340 using button
The power on scenarios illustrates as following figure.
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