ATTINY13V_14 Datasheet, PDF (31/176 Pages) ATMEL Corporation – High Endurance Non-volatile Memory segments

ATtiny13
7.1.2
7.1.3
Control and Status Register – ACSR. This will reduce power consumption in Idle mode. If the
ADC is enabled, a conversion starts automatically when this mode is entered.
ADC Noise Reduction Mode
When the SM[1:0] bits are written to 01, the SLEEP instruction makes the MCU enter ADC
Noise Reduction mode, stopping the CPU but allowing the ADC, the external interrupts, and the
Watchdog to continue operating (if enabled). This sleep mode halts clk_I/O, clk_CPU, and clk_FLASH,
while allowing the other clocks to run.
This improves the noise environment for the ADC, enabling higher resolution measurements. If
the ADC is enabled, a conversion starts automatically when this mode is entered. Apart form the
ADC Conversion Complete interrupt, only an External Reset, a Watchdog Reset, a Brown-out
Reset, an SPM/EEPROM ready interrupt, an external level interrupt on INT0 or a pin change
interrupt can wake up the MCU from ADC Noise Reduction mode.
Power-down Mode
When the SM[1:0] bits are written to 10, the SLEEP instruction makes the MCU enter Power-
down mode. In this mode, the Oscillator is stopped, while the external interrupts, and the Watch-
dog continue operating (if enabled). Only an External Reset, a Watchdog Reset, a Brown-out
Reset, an external level interrupt on INT0, or a pin change interrupt can wake up the MCU. This
sleep mode halts all generated clocks, allowing operation of asynchronous modules only.
7.2 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.
7.2.1
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 81 for
details on ADC operation.
7.2.2
7.2.3
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 dis-
abled in all sleep modes. Otherwise, the Internal Voltage Reference will be enabled,
independent of sleep mode. Refer to “Analog Comparator” on page 78 for details on how to con-
figure the Analog Comparator.
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 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 Detection” on page 36 for details on how to
configure the Brown-out Detector.
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2535J–AVR–08/10