Datasheet

6. Function Description 37
6.4.5 Power Down Mode
6.4.5.1 Changes in Power Down Mode
The Power Down Mode is entered using the command AT^SMSO.
The GSM engine switches itself off, only the RTC is still active.
The following routine takes place with AT^SMSO:
AT^SMSO
^SMSO: MS OFF
OK
^SHUTDOWN
In the power down mode, the serial interface is inactive, the outputs (RXS, CTS, DCD, DSR,
and RI) are highly resistive.
To avoid “floating” of the according inputs of the application in that case, these inputs
should have pull-up or pull-down resistors.
In power down mode the INSYS GSM small is not registered at the GSM network.
ATTENTION: Besides shutting down the GSM engine, the command AT^SMSO has a
second function as well. Some of the extended AT commands can only be stored using
this command (AT^SCFG, AT+CSNS, AT^SCKS, AT+CALA).
After entering AT^SMSO it is therefore required to wait for the response ^SHUTDOWN,
before the supply voltage is disconnected.
As for each shutdown, data is written into the non-volatile memory of the GSM engine
with AT^SMSO , the maximum number of “shutdowns” is limited to 100,000.
6.4.5.2 Power Down RTC and Alarm Mode
As the internal real time clock (RTC) keeps running in power down mode, the alarm
function of the RTC (AT+CALA) can be used to switch the INSYS GSM small from power
down into RTC alarm mode.
If a set RTC alarm occurs during the time period in which the INSYS GSM small is in
power down mode, the RTC alarm mode is entered with the following message:
^SYSSTART ALARM MODE
[+CALA: <text>]
Version 1.00 / 09.04