Digitax 4GMCU, Техническое руководство, Страница: 17 / 64

17
Power management and Stealth Mode
The power management is designed to perform several tasks:
Manual power switch ON/OFF
Automatic shut down in case of black-out
UPS function to allow proper shut down in case of a power failure event
Managing the power supply of the on board peripherals (GPS, GSM/GPRS)
A dedicated CPU (AITP) is used in order to manage such functions, and is permanently powered even
when the MCU is Off, it stands by for any pressure of the ON/OFF front panel switch or of for the
GSM Ring signal.
The voltage of the main battery and the UPS battery is permanently checked by the system.
4GMCU Power On
Regular power on
When the device is powered OFF, a short pressure on the power switch will turn ON the entire MCU.
Boot is made from the Hard Disk, making all system backup/restore/update procedures as described
in the previous chapters.
At Window start, a system application called
Autorun is executed, managing also firmware upgrades,
and after that the user application is run.
Alternative power on
In case of system disk failures, alternative boot from the System Disk is possible by pressing the
power button for more than 15 seconds. If a bootable SD Card is inserted during start-up, a boot
from the SD Card is possible in the same way.
Wake up on Ring / Stealth Mode
AITP can be configured to start automatically the MCU when it detects a GSM RING signal, from a
voice or data call to the terminal. In this case the MCU can be started in the normal way or in Stealth
Mode, which is with an hidden interface, in order to monitor the environment. TFT display is Off,
Leds are Off, no sound is emitted unless desired by the user application.
Applications have to detect Stealth Mode by asking to AITP, and eventually come back to the normal
mode without rebooting or modifying Stealth Mode settings.
Power ON using external imput
It is also possible to power ON the MCU using a low to high transition on special input 3. A Power On
timer can be setup to turn ON after a specified time from input signal. The MCU is started with the
regular Power ON procedure. If power button is kept pressed for at least 15 seconds, and then a
special input 3 is driven high without releasing the button, finally the MCU is powered using the
alternate boot procedure.
4GMCU Power Off
Regular Power Off
While the device is ON, pressing the power switch for more than 2 seconds causes the beginning of
the Windows Shut Down procedure.
Even in case of Windows not responding the AITP forces power off.