User's Manual

GWM300 Hardware Interface Overview
3.5 Power Up/Power Down Scenarios
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 GWM300_HIO_v01 2016-01-26
Confidential / Released
Page 24 of 35
3.5 Power Up/Power Down Scenarios
In general, be sure not to turn on the GWM300 while it is beyond the safety limits of voltage
stated in Section 4.1. GWM300 immediately switches off after having started and detected
these inappropriate conditions. In extreme cases this can cause permanent damage to the
GWM300.
3.5.1 Turn GWM300 on
GWM300 is automatically turned on and started into normal mode by plugging or by re-plug-
ging an appropriate power supply unit at the power supply line BATT+.
3.5.2 Reset/Restart GWM300
GWM300 can be reset/restarted by entering the command AT+CFUN=x,1. For details on
AT+CFUN please see [1].
3.5.3 Turn GWM300 off
Normal shutdown:
• To turn off the GWM300 use the AT^SMSO command, rather than disconnecting the mains
adapter.
This switch off procedure lets the GWM300 log off from the network and allows the software
to enter a secure state and save data before disconnecting the power supply. After
AT^SMSO has been entered the GWM300 returns the following result codes:
^SMSO: MS OFF
OK
^SHUTDOWN
The "^SHUTDOWN" result code indicates that the GWM300 turns off in less than 1 second.
After the shutdown procedure is complete the GWM300 enters the Power Down mode. The
RTC is still fed from the voltage regulator in the power supply ASIC.
Only after power off and power on again, i.e., turning off and on the power supply line, can the
terminal be switches on again. Apart from teh normal shutdown
3.5.4 Disconnecting Power Supply
Before disconnecting the power supply from the BATT+ pin, make sure that the GWM300 is in
a safe condition. The best way is to wait 1s after the "^SHUTDOWN" result code has been in-
dicated.