Espressif ESP32-S2 User Manual

Chapter 2. API Reference
Max CPU Frequency Set Lock Acquisition CPU and APB Frequncies
240 ESP_PM_CPU_FREQ_MAX
acquired
CPU: 240 MHz
APB: 80 MHz
ESP_PM_APB_FREQ_MAX
acquired,
ESP_PM_CPU_FREQ_MAX
not acquired
CPU: 80 MHz
APB: 80 MHz
None Min values for both frequencies set
with esp_pm_configure()
160 ESP_PM_CPU_FREQ_MAX
acquired
CPU: 160 MHz
APB: 80 MHz
ESP_PM_APB_FREQ_MAX
acquired,
ESP_PM_CPU_FREQ_MAX
not acquired
CPU: 80 MHz
APB: 80 MHz
None Min values for both frequencies set
with esp_pm_configure()
80
Any of
ESP_PM_CPU_FREQ_MAX
or ESP_PM_APB_FREQ_MAX
acquired
CPU: 80 MHz
APB: 80 MHz
None Min values for both frequencies set
with esp_pm_configure()
If none of the locks are acquired, and light sleep is enabled in a call to 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 High resolution timer APIs
Light sleep duration will be chosen to wake up the chip before the nearest event (task being unblocked, or timer
elapses).
To skip unnecessary wake-up you can consider initializing an esp_timer with the skip_unhandled_events option as
true. Timers with this flag will not wake up the system and it helps to reduce consumption.
Dynamic Frequency Scaling and Peripheral Drivers
When DFS is enabled, the APB frequency can be changed multiple times within a single RTOS tick. The APB
frequency change does not affect the operation of some peripherals, while other peripherals may have issues. For
example, Timer Group peripheral timers will keep counting, however, the speed at which they count will change
proportionally to the APB frequency.
The following peripherals work normally even when the APB frequency is changing:
• UART: if REF_TICK is used as a clock source. See use_ref_tick member of uart_config_t.
• LEDC: if REF_TICK is used as a clock source. See ledc_timer_config() function.
• RMT: if REF_TICK or XTAL is used as a clock source. See flags member of rmt_config_t and macro
RMT_CHANNEL_FLAGS_AWARE_DFS.
Espressif Systems 1032
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Espressif ESP32-S2 Specifications

General

Brand	Espressif
Model	ESP32-S2
Category	Single board computers
Language	English