If the MCU is continuously active, its power consumption increases. In most applications, it is desirable to minimize the power consumption, but not to reduce the system clock frequency. This is mainly to ensure fast processing and quick response of the system. In such applications, the use of sleep modes of the AVR XMEGA devices are to keep the device in a low-power state when there is nothing to process. The main principle is to run as fast as possible and sleep as much as possible. Running as fast as possible reduces the effect of static power consumption (i.e. independent of clock frequency), e.g.; due to non-volatile memory being enabled in Active mode.
Most commonly available sleep modes are Idle, Power-down, Power-save, Standby, and Extended Standby. Each sleep mode utilizes a different set of peripherals. Among these sleep modes, the Power-down mode is the best sleep mode since this mode shuts down almost all the peripherals resulting in good power reduction. Based on application power requirements, active and sleep duration of the device can be configured.
Keep the device in active mode for a defined shorter duration and in sleep mode for a longer duration.