Power Mode Switching Process
A typical power mode switching process is as follows (suppose Bluetooth LE subsystem and peripherals are used at the same time):
- The system enters the cold boot process after power-on.
- Enter active mode.
- When no task is pending, the system starts to check whether the system is idle (Check Sleep in the process diagram above)
- If the result is Yes, detect the remaining idle time (for example, the due time for Bluetooth LE Timer, Sleep Timer, and RTC). If the due time is shorter than warm boot process, the system enters idle mode; if the due time is longer than warm boot process, the system enters sleep mode, and waits to be woken up by a wake-up source.
- If the result is No, the system stays in active mode.
Note:
Boot time and high boot current are required for the system to enter the warm boot process from sleep mode. When sleep time is relatively short (for example, shorter than 2s), the power consumption reduced is hardly noticeable. Therefore, to ensure overall performance, the system enters sleep mode only when sleep time is longer, so that the average power consumption can be reduced.
