esp-idf/docs/en/api-reference/system/inc/power_management_esp32.rst

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ESP32 Power Management Algorithm
--------------------------------
The table below shows how CPU and APB frequencies will be switched if dynamic frequency scaling is enabled. You can specify the maximum CPU frequency with either :cpp:func:`esp_pm_configure` or :ref:`CONFIG_ESP32_DEFAULT_CPU_FREQ_MHZ`.
+---------------+---------------------------------------+-------------------------------------+
| Max CPU | Lock Acquisition | CPU and APB Frequncies |
| Frequency Set | | |
+---------------+---------------------------------------+-------------------------------------+
| 240 | | Any of ``ESP_PM_CPU_FREQ_MAX`` | |
| | | or ``ESP_PM_APB_FREQ_MAX`` acquired | | CPU: 240 MHz |
| | | | APB: 80 MHz |
+ +---------------------------------------+-------------------------------------+
| | None | Min values for both frequencies set |
| | | with :cpp:func:`esp_pm_configure` |
+---------------+---------------------------------------+-------------------------------------+
| 160 | ``ESP_PM_CPU_FREQ_MAX`` acquired | | CPU: 160 MHz |
| | | | APB: 80 MHz |
+ +---------------------------------------+-------------------------------------+
| | ``ESP_PM_CPU_FREQ_MAX`` acquired, | | CPU: 80 MHz |
| | ``ESP_PM_APB_FREQ_MAX`` not acquired | | APB: 80 MHz |
+ +---------------------------------------+-------------------------------------+
| | None | Min values for both frequencies set |
| | | with :cpp:func:`esp_pm_configure` |
+---------------+---------------------------------------+-------------------------------------+
| 80 | | Any of ``ESP_PM_CPU_FREQ_MAX`` | | CPU: 80 MHz |
| | | or ``ESP_PM_APB_FREQ_MAX`` acquired | | APB: 80 MHz |
+ +---------------------------------------+-------------------------------------+
| | None | Min values for both frequencies set |
| | | with :cpp:func:`esp_pm_configure` |
+---------------+---------------------------------------+-------------------------------------+
If none of the locks are acquired, and light sleep is enabled in a call to :cpp:func:`esp_pm_configure`, the system will go into light sleep mode. The duration of light sleep will be determined by:
- FreeRTOS tasks blocked with finite timeouts
- Timers registered with :doc:`High resolution timer <esp_timer>` APIs
Light sleep duration will be chosen to wake up the chip before the nearest event (task being unblocked, or timer elapses).