Rainbow Electronics ATtiny2313 - Manual (Page 32)

32
ATtiny2313
2543A–AVR–08/03
Minimizing Power
Consumption There are several issues to consider when trying to minimize the power consumption in
an AVR controlled system. In general, sleep modes should be used as much as possi-
ble, and the sleep mode should be selected so that as few as possible of the device’s
functions are operating. All functions not needed should be disabled. In particular, the
following modules may need special consideration when trying to achieve the lowest
possible power consumption.
Analog Comparator When entering Idle mode, the Analog Comparator should be disabled if not used. In
other sleep modes, the Analog Comparator is automatically disabled. However, if the
Analog Comparator is set up to use the Internal Voltage Reference as input, the Analog
Comparator should be disabled in all sleep modes. Otherwise, the Internal Voltage Ref-
erence will be enabled, independent of sleep mode. Refer to “Analog Comparator” on
page 151 for details on how to configure the Analog Comparator.
Brown-out Detector If the Brown-out Detector is not needed by the application, this module should be turned
off. If the Brown-out Detector is enabled by the BODLEVEL Fuses, it will be enabled in
all sleep modes, and hence, always consume power. In the deeper sleep modes, this
will contribute significantly to the total current consumption. Refer to “Brown-out Detec-
tion” on page 36 for details on how to configure the Brown-out Detector.
Internal Voltage Reference The Internal Voltage Reference will be enabled when needed by the Brown-out Detec-
tion or the Analog Comparator. If these modules are disabled as described in the
sections above, the internal voltage reference will be disabled and it will not be consum-
ing power. When turned on again, the user must allow the reference to start up before
the output is used. If the reference is kept on in sleep mode, the output can be used
immediately. Refer to “Internal Voltage Reference” on page 39 for details on the start-up
time.
Watchdog Timer If the Watchdog Timer is not needed in the application, the module should be turned off.
If the Watchdog Timer is enabled, it will be enabled in all sleep modes, and hence,
always consume power. In the deeper sleep modes, this will contribute significantly to
the total current consumption. Refer to “Interrupts” on page 45 for details on how to con-
figure the Watchdog Timer.