Turn Off The Gsm Part - SimCom SIM548C HD V1.01 Hardware Design

SIM548C Hardware Design
for details of the instructions refer to document [1]:
Table 7: AT commands used in Alarm mode
AT command
AT+CALARM
AT+CCLK
AT+CPOWD
AT+CFUN

3.4.2 Turn off the GSM part

Following procedure can be used to turn off the GSM part of SIM548C:
Normal power down procedure: Turn off the GSM part of SIM548C using the PWRKEY pin
Normal power down procedure: Turn off the GSM part of SIM548C using AT command
Over-voltage or under-voltage automatic shutdown: Take effect if over-voltage or
under-voltage is detected
Over-temperature or under-temperature Automatic shutdown: Take effect if over-temperature
or under-temperature is detected
3.4.2.1 Turn off the GSM part using the PWRKEY pin (Power down)
You can turn off the GSM part of SIM548C by driving the PWRKEY to a low level voltage for
some time. Please refer to the turn on circuit. The power down scenarios illustrate as figure 4.
This procedure lets the module log off from the network and allows the software to enter into a
secure state and save data before completely disconnecting the power supply.
Before the completion of the switching off procedure the module will send out result code:
NORMAL POWER DOWN
After this moment, the AT commands can't be executed. The module enters the POWER DOWN
mode, only the RTC is still active. POWER DOWN can also be indicated by STATUS pin, which
is a low level voltage in this mode.
SIM548C_HD_V1.01
USE
Set alarm time
Set data and time of RTC
Power down
Start or close the protocol stack
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09.05.2008