Eurotech CPU-1450, Руководство пользователя, Страница: 22 / 43

SPM Management 22
Entering Low Power mode
This chapter describes how to enter the low-power mode and the events that allow the user to wake-up the
CPU-1450 from the sleep state.
To minimize power consumption the CPU has to be placed into a low power consumption mode, this may be
done via software.
ATX Power Button
If you use the ATX power-button you can shutdown the System as a standard ATX PC whenever you want,
this is not a correct mode to manage the SPM mode, because, in this way your application does not have
any information regarding the power on/off modes.
When you experiment with the Soft Power Management using the development kit remember to leave the
ATX power button in the power off position.
External Power Button
The external Power Button (PWR_BTN pin 10 of the J11 connector) has to be connected between pin 10
and 7 of the J11 connector to allow the user to power-down or power-up the CPU. This feature may be
enabled or disabled by writing the appropriate values on the ICH2 registers.
Looking at the
Error! Reference source not found. users can analyse the PWR_BTN signal path that can
be routed via the JPR2 to the ICH2 82801 or the Super I/O PC87364. By default the PWR_BTN signal is
routed to the ICH2 chipset.
Currently this functionality is not implemented.
Software
An0065. CPU-1450 Soft Power Management
You can enter Low Power Mode by writing to the appropriate register using software; this allows you to
shutdown the CPU remotely. The SPM may be managed by software by programming the Software Power
Down Registers as described later in this document.