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User
’
s Manual
2-18
1999-08
2.4
Power Management Features
The known basic power reduction modes (Idle and Power Down) are enhanced by a
number of additional power management features (see below). These features can be
combined to reduce the controller
’
s power consumption to the respective application
’
s
possible minimum.
Flexible clock generation
Flexible peripheral management (peripherals can be dis/unabled separately or in groups)
Periodic wakeup from Idle mode via RTC timer
The listed features provide effective means to realize standby conditions for the system
with an optimum balance between power reduction (i.e. standby time) and peripheral
operation (i.e. system functionality).
Flexible Clock Generation
The flexible clock generation system combines a variety of improved mechanisms (partly
user controllable) to provide the C161PI modules with clock signals. This is especially
important in power sensitive modes like standby operation.
The power optimized oscillator
generally reduces the amount of power which is
consumed in order to generate the clock signal within the C161PI.
The clock system
efficiently controls the amount of power which is consumed in order
to distribute the clock signal within the C161PI.
Slowdown operation
is achieved by dividing the oscillator clock by a programmable
factor (1...32) resulting in a low frequency device operation which significantly reduces
the overall power consumption.
Flexible Peripheral Management
The flexible peripheral management provides a mechanism to enable and disable each
peripheral module separately. In each situation (e.g. several system operating modes,
standby, etc.) only those peripherals may be kept running which are required for the
respective functionality. All others can be switched off. It also allows the operation control
of whole groups of peripherals including the power required for generating and
distributing their clock input signal. Other peripherals may remain active, e.g. in order to
maintain communication channels. The registers of separately disabled peripherals (not
within a disabled group) can still be accessed.