BGS3 Hardware Interface Description
3.3 Power Up / Power Down Scenarios
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BGS3_HD_v01.000d
Page 32 of 109
2010-03-26
Confidential / Released
3.3.3
Turn off BGS3
BGS3 can be turned off as follows:
•
Normal shutdown: Software controlled by AT^SMSO command
•
Automatic shutdown: Takes effect if board or battery temperature is out of range or if und-
ervoltage or overvoltage conditions occur.
3.3.3.1
Turn off BGS3 Using AT Command
The best and safest approach to powering down BGS3 is to issue the AT^SMSO command.
This procedure lets BGS3 log off from the network and allows the software to enter into a se-
cure state and safe data before disconnecting the power supply. The mode is referred to as
Power-down mode. In this mode, only the RTC stays active.
Before switching off the device sends the following response:
^SMSO: MS OFF
OK
^SHUTDOWN
After sending AT^SMSO do not enter any other AT commands. There are two ways to verify
when the module turns off:
•
Wait for the URC “^SHUTDOWN”. It indicates that data have been stored non-volatile and
the module turns off in less than 1 second.
•
Also, you can monitor the PWR_IND signal. High state of PWR_IND definitely indicates that
the module is switched off.
Be sure not to disconnect the supply voltage V
BATT+
before the URC “^SHUTDOWN” has been
issued and the PWR_IND signal has gone high. Otherwise you run the risk of losing data. Sig-
nal states during turn-off are shown in
DAI3
I
O, L
O, L
DAI4 I
Tristate
I
DAI5 I
Tristate
I
DAI6
I
Tristate
I
1. Before reaching the defined state the signal has the intermediate state O, H for about 2s.
2. Before reaching the defined state the signal has the intermediate states O, H for about 2s and O, L for
about 1s.
3. Before reaching the defined state the signal has the intermediate state O, H for about 0.5s.
Table 8:
Signal states
Signal name
Undefined state during
startup
Defined state after
startup initialization
Active state after
configuration by
AT command
DAI
