UM0704
System operation
Doc ID 15731 Rev 1
11/18
2.3 Battery
life
monitoring
The system is continuously monitoring the battery life and the user can check the present
status of the battery at any time by pressing the mode switch twice (maximum 800 ms
between two consecutive key presses). The higher the number of LEDs glowing; the more
battery life remains (see
).
Figure 12.
Battery status
When the battery voltage falls below 3.2 V, the system gives a low battery warning in which
all the LEDs turn off and the complete system goes into low power mode. The system does
not operate from the low power mode. This is an indication to the user that the batteries
need to be replaced immediately. The system doesn’t work until the batteries are replaced.
Note:
The display levels are just to indicate to the user the battery life which is capable of running
the system successfully.
2.4 Free-fall
detection
The system is capable of detecting the free-fall of the board. Normally, the central D21 LED
of the board is green. As the board is given a free-fall motion, the system produces a
warning sound and the bi-color LED turns red. The inner circle blinks five times after the
free-fall motion is detected. After the board has recovered from the free-fall motion, the bi-
color LED turns green.
Note:
The system only recognizes the free-fall of the board and rejects a forceful throw.
2.5 Standby
operation
The system is provided with smart intelligence to save power. If the system is not disturbed
or doesn’t detect any motion for more than 10 seconds, then the system switches into the
standby mode. In this mode all the LEDs are OFF and the MEMS and MCU are at their low-
power consumption configuration. The system is smart enough that, as soon as it detects
any motion, it wakes up from standby and starts performing in the same mode in which it
went into standby. The system can also be re-activated by pressing the mode switch.
Note:
The standby operation of the system is not present in the demonstration modes. This is
done for the continuous operation of the system in demonstration modes.
AM042
3
10v1
www.BDTIC.com/ST
