ATmega165 datasheet(35/336 Pages) ATMEL

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ATmega165/V

2573G–AVR–07/09

• Bit 2 - PRSPI: Power Reduction Serial Peripheral Interface

Writing a logic one to this bit shuts down the Serial Peripheral Interface by stopping the

clock to the module. When waking up the SPI again, the SPI should be re initialized to

ensure proper operation.

• Bit 1 - PRUSART0: Power Reduction USART0

Writing a logic one to this bit shuts down the USART by stopping the clock to the mod-

ule. When waking up the USART again, the USART should be re initialized to ensure

proper operation.

• Bit 0 - PRADC: Power Reduction ADC

Writing a logic one to this bit shuts down the ADC. The ADC must be disabled before

shut down. The analog comparator cannot use the ADC input MUX when the ADC is

shut down.

Note:The Analog Comparator is disabled using the ACD bit in the “Analog Comparator Control

and Status Register – ACSR” on page 186.

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 to Digital Converter

If enabled, the ADC will be enabled in all sleep modes. To save power, the ADC should

be disabled 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 Con-

verter” on page 189 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

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 186 for details on how to configure the Analog Comparator.

ATmega165 Arkusz danych(PDF) 35 Page - ATMEL Corporation