User's Manual

1.11 SUSPEND MANAGEMENT
Suspend Management allows the user to keep device features powered while the
device is off.
The features managed by this feature are: Cellular Data/Voice and GPS.
The WiFi driver has been measured to consume about 50 µA when
left powered. As a result, WiFi will always be left powered during
suspend. This has the positive effect of substantially reducing the
time required for WiFi to fully resume when the device is powered
back on.
NOTE
Normally, the device features will behave the same as today. This means when the
device is powered off, certain features (such as cellular communications) will remain
powered if enabled prior to the device powering off. The behavior of each feature left
powered during suspend is as follows:
 Power is not removed from the feature.
 It can act as a wakeup source for the CPU. When the CPU wakes up, the
device continues to appear "off", but the device driver on the CPU can interact
with the feature.
 Depending on what activity takes place, any feature can optionally decide to
change the system power state from Suspend to On. This would appear to the
user as a wakeup event.
When the user powers off the device by pressing the power key, the behavior begins
similar to today:
 The user is required to press the power key for at least 500 ms.
 After this much time, the red suspend LED turns on to provide user feedback
that the power key has been recognized.
If the user releases the power key in the next 1.5 seconds, the system completes the
shutdown of the CPU and device features will remain powered. If instead the user
continues to hold down the power key for a total of at least two seconds, then the
following pop-up dialog will be displayed: