The majority of platforms have at least three different operating modes: - Running - The default operating state where we have full functionality. - Sleep/Suspend - Main processor is suspended to RAM. This is a power-saving mode where as much as possible is powered down to minimize the power consumption while maintaining a fast resume time (around 1 s) to running state. - Deep sleep - The main processor is powered off and only the coprocessor is running in low-power mode. - Shutdown/Cut-off - The machine has almost no power consumption as the main regulator is turned off. See start signal
The machine can wake up from different sources but the Real time clock and CAN are most often used. The list of wake-up sources is platform specific and depending on the sleep mode. For
Shutdown/Cutoff, for example, only start signal input is supported.