ATmega64A
Table 9-1.
Active Clock Domains and Wake Up Sources in the Different Sleep Modes
Active Clock Domains Oscillators
Wake Up Sources
Sleep
Mode
Idle
X
X
X
X
X
X
X(2)
X(2)
X
X
X
X
X
X
X
X
X
X
ADC
Noise
X
X(3)
Reduction
Power-
down
X(3)
X
Power-
save
X(2)
X(2)
X(3)
X(3)
X(3)
X
X
X
X(2)
Standby(1)
X
X
Extended
Standby(1)
X(2)
X(2)
X(2)
Notes: 1. External Crystal or resonator selected as clock source.
2. If AS0 bit in ASSR is set.
3. Only INT3:0 or level interrupt INT7:4.
9.7
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 possible, 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.
9.7.1
9.7.2
Analog to Digital Converter
If enabled, the ADC will be enabled in all sleep modes. To save power, the ADC should be dis-
abled before entering any sleep mode. When the ADC is turned off and on again, the next
conversion will be an extended conversion. Refer to “Analog to Digital Converter” on page 233
for details on ADC operation.
Analog Comparator
When entering Idle mode, the Analog Comparator should be disabled if not used. When entering
ADC Noise Reduction mode, the Analog Comparator should be disabled. In the 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 reference will be enabled, independent of
sleep mode. Refer to “Analog Comparator” on page 230 for details on how to configure the Ana-
log Comparator.
9.7.3
Brown-out Detector
If the Brown-out Detector is not needed in the application, this module should be turned off. If the
Brown-out Detector is enabled by the BODEN Fuse, it will be enabled in all sleep modes, and
48
8160C–AVR–07/09
ATMEL [ ATMEL ]
