Power consumption verification


What sleep modes does ESP32 have? What is the difference between them?

ESP32 has three sleep modes: Modem-sleep, Light-sleep, and Deep-sleep.

  • Modem-sleep:

    • The Station Legacy Fast sleep mode specified in the Wi-Fi specification, in which the Station sends a NULL frame to notify the AP to sleep or wake up.

    • After the station is connected to the AP, the station is automatically turned on. After the station enters the Modem-sleep mode, the RF module is shut down. During the modem sleep, the connection to the AP is maintained. After the AP disconnects from the station, Modem-sleep does not work.

    • After ESP32 enters Modem-sleep mode, the CPU clock frequency can be lowered to further reduce the current.

  • Light-sleep:

    • A Station sleep mode based on Modem-sleep;

    • The differences between Light-sleep and Modem-sleep are:

      • After ESP32 enters the Light-sleep mode, not only the RF module but also the CPU and part of the system clock are suspended.

      • After ESP32 exits the Light-sleep mode, the CPU resumes working.

  • Deep-sleep:

    • A sleep mode that is not specified in the Wi-Fi specification;

    • After ESP32 enters the Deep-sleep mode, all modules are closed except for RTC modules;

    • After ESP32 exits the Deep-sleep mode, the entire system reruns, which is similar to the system reboot;

    • During the deep sleep, no connection to the AP is maintained.