The different operating modes of the SAM3U are shown on this slide. Active mode is the mode when the device is running at full speed. There are three low-power modes: sleep mode, previously called idle mode, when the clock of the core is disabled and the system runs at 500 Hz, wait mode and backup mode. There are two new modes: wait mode and backup mode. In wait mode, wake up occurs very quickly, in less than 10 µs, and power consumption is 8 µA typically. Backup mode is when only the backup unit is powered, that is the RTC, the RTT and the backup registers. It gives the lowest raw power consumption at 2.5 µA typically. Again, there is a trade off to make between wake-up time and power consumption: for fastest wake-up, the best choice is wait mode, for lowest power consumption the best mode is backup mode.