Revision as of 23:40, 28 February 2013

Funktion

Versetzt den Mikrocontroller in einen der unterstützten Stromspar-Modi.

Syntax

CONFIG POWERMODE mode

Remarks

The mode depends on the micro processor.

Some valid options are :

- IDLE

- POWERDOWN

- STANDBY

- ADCNOISE

- POWERSAVE

The modes and their exact behaviour is different on all processors. The following description from the datasheet is for the Mega88P.

IDLE MODE

The Idle mode will stop the CPU but allowing the SPI, USART, Analog Comparator, ADC, 2-wire Serial

Interface, Timer/Counters, Watchdog, and the interrupt system to continue operating. This sleep

mode basically halts clkCPU and clkFLASH, while allowing the other clocks to run.

Idle mode enables the MCU to wake up from external triggered interrupts as well as internal

ones like the Timer Overflow and USART Transmit Complete interrupts. If wake-up from the

Analog Comparator interrupt is not required, the Analog Comparator can be powered down by

setting the ACD bit in the Analog Comparator 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

This mode will stop the CPU but allowing the ADC, the external interrupts, the 2-

wire Serial Interface address watch, Timer/Counter2(1), and the Watchdog to continue operating

(if enabled). This sleep mode basically halts clkI/O, clkCPU, and clkFLASH, 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 from the

ADC Conversion Complete interrupt, only an External Reset, a Watchdog System Reset, a

Watchdog Interrupt, a Brown-out Reset, a 2-wire Serial Interface address match, a

Timer/Counter2 interrupt, an SPM/EEPROM ready interrupt, an external level interrupt on INT0

or INT1 or a pin change interrupt can wake up the MCU from ADC Noise Reduction mode.

POWERDOWN

In this mode, the external Oscillator is stopped, while the external interrupts, the 2-

wire Serial Interface address watch, and the Watchdog continue operating (if enabled). Only an

External Reset, a Watchdog System Reset, a Watchdog Interrupt, a Brown-out Reset, a 2-wire

Serial Interface address match, an external level interrupt on INT0 or INT1, or a pin change

interrupt can wake up the MCU. This sleep mode basically halts all generated clocks, allowing

operation of asynchronous modules only.

Note that if a level triggered interrupt is used for wake-up from Power-down mode, the changed

level must be held for some time to wake up the MCU.

When waking up from Power-down mode, there is a delay from the wake-up condition occurs

until the wake-up becomes effective. This allows the clock to restart and become stable after

having been stopped. The wake-up period is defined by the same CKSEL Fuses that define the

Reset Time-out period, as described in ”Clock Sources”

POWERSAVE

This mode is identical to Power-down, with one exception:

If Timer/Counter2 is enabled, it will keep running during sleep. The device can wake up from

either Timer Overflow or Output Compare event from Timer/Counter2 if the corresponding

Timer/Counter2 interrupt enable bits are set in TIMSK2, and the Global Interrupt Enable bit in

SREG is set.

If Timer/Counter2 is not running, Power-down mode is recommended instead of Power-save

mode.

The Timer/Counter2 can be clocked both synchronously and asynchronously in Power-save

mode. If Timer/Counter2 is not using the asynchronous clock, the Timer/Counter Oscillator is

stopped during sleep. If Timer/Counter2 is not using the synchronous clock, the clock source is

stopped during sleep. Note that even if the synchronous clock is running in Power-save, this

clock is only available for Timer/Counter2.

STANDBY

This mode is identical to Power-down

with the exception that the Oscillator is kept running. From Standby mode, the device wakes up

in six clock cycles.

EXTENDED STANDBY

This mode is identical to

Power-save with the exception that the Oscillator is kept running. From Extended Standby

mode, the device wakes up in six clock cycles.

So for standby you would use :  POWER STANDBY

It is also possible to use POWERDOWN, IDLE or POWERSAVE. These modes were/are supported by most processors. It is recommended to use the new CONFIG POWERMODE command because it allows to use more modes.

See also

IDLE, POWERDOWN , POWERSAVE

Beispiel

CONFIG POWERMODE = IDLE