# Clock Tree

[中文]

The clock subsystem of ESP32-P4 is used to source and distribute system/module clocks from a range of root clocks. The clock tree driver maintains the basic functionality of the system clock and the intricate relationship among module clocks.

This document starts with the introduction to root and module clocks. Then it covers the clock tree APIs that can be called to monitor the status of the module clocks at runtime.

## Introduction

This section lists definitions of ESP32-P4's supported root clocks and module clocks. These definitions are commonly used in the driver configuration, to help select a proper source clock for the peripheral.

### Root Clocks

Root clocks generate reliable clock signals. These clock signals then pass through various gates, muxes, dividers, or multipliers to become the clock sources for every functional module: the CPU core(s), Wi-Fi, Bluetooth, the RTC, and the peripherals.

ESP32-P4's root clocks are listed in `soc_root_clk_t`:

> - Internal 17.5 MHz RC Oscillator (RC_FAST)

>   > This RC oscillator generates a about 17.5 MHz clock signal output as the `RC_FAST_CLK`.

>   > The exact frequency of `RC_FAST_CLK` can be computed in runtime through calibration.

> - External 40 MHz Crystal (XTAL)

> - Internal 136 kHz RC Oscillator (RC_SLOW)

>   > This RC oscillator generates a about 136kHz clock signal output as the `RC_SLOW_CLK`. The exact frequency of this clock can be computed in runtime through calibration.

> - External 32 kHz Crystal - optional (XTAL32K)

>   > The clock source for this `XTAL32K_CLK` is a 32 kHz crystal connecting to the `XTAL_32K_P` and `XTAL_32K_N` pins.

>   > `XTAL32K_CLK` can also be calibrated to get its exact frequency.

Typically, the frequency of the signal generated from an RC oscillator circuit is less accurate and more sensitive to the environment compared to the signal generated from a crystal. ESP32-P4 provides several clock source options for the `RTC_SLOW_CLK`, and it is possible to make the choice based on the requirements for system time accuracy and power consumption. For more details, please refer to RTC Timer Clock Sources.

### Module Clocks

ESP32-P4's available module clocks are listed in `soc_module_clk_t`. Each module clock has a unique ID. You can get more information on each clock by checking the documented enum value.

## API Usage

The clock tree driver provides an all-in-one API to get the frequency of the module clocks, `esp_clk_tree_src_get_freq_hz()`. This function allows you to obtain the clock frequency at any time by providing the clock name `soc_module_clk_t` and specifying the desired precision level for the returned frequency value `esp_clk_tree_src_freq_precision_t`.

## API Reference

### Header File

- components/soc/esp32p4/include/soc/clk_tree_defs.h

- This header file can be included with:

  >     #include "soc/clk_tree_defs.h"

### Macros

SOC_CLK_RC_FAST_FREQ_APPROX

  Approximate RC_FAST_CLK frequency in Hz

SOC_CLK_RC_SLOW_FREQ_APPROX

  Approximate RC_SLOW_CLK frequency in Hz

SOC_CLK_RC32K_FREQ_APPROX

  Approximate RC32K_CLK frequency in Hz

SOC_CLK_XTAL32K_FREQ_APPROX

  Approximate XTAL32K_CLK frequency in Hz

SOC_GPTIMER_CLKS

  Array initializer for all supported clock sources of GPTimer.

  The following code can be used to iterate all possible clocks:

      soc_periph_gptimer_clk_src_t gptimer_clks[] = (soc_periph_gptimer_clk_src_t)SOC_GPTIMER_CLKS;
      for (size_t i = 0; i< sizeof(gptimer_clks) / sizeof(gptimer_clks[0]); i++) {
          soc_periph_gptimer_clk_src_t clk = gptimer_clks[i];
          // Test GPTimer with the clock `clk`
      }

SOC_RMT_CLKS

  Array initializer for all supported clock sources of RMT.

SOC_UART_CLKS

  Array initializer for all supported clock sources of UART.

SOC_LP_UART_CLKS

  Array initializer for all supported clock sources of LP_UART.

SOC_MCPWM_TIMER_CLKS

  Array initializer for all supported clock sources of MCPWM Timer.

SOC_MCPWM_CAPTURE_CLKS

  Array initializer for all supported clock sources of MCPWM Capture Timer.

SOC_MCPWM_CARRIER_CLKS

  Array initializer for all supported clock sources of MCPWM Carrier.

SOC_I2S_CLKS

  Array initializer for all supported clock sources of I2S.

SOC_LP_I2S_CLKS

  Array initializer for all supported clock sources of LP I2S.

SOC_LCD_CLKS

  Array initializer for all supported clock sources of LCD.

SOC_CAM_CLKS

  Array initializer for all supported clock sources of CAM.

SOC_MIPI_CSI_PHY_CLKS

  Array initializer for all supported clock sources of MIPI CSI PHY interface.

SOC_MIPI_DSI_DPI_CLKS

  Array initializer for all supported clock sources of MIPI DSI DPI interface.

SOC_MIPI_DSI_PHY_CLKS

  Array initializer for all supported clock sources of MIPI DSI PHY interface.

SOC_I2C_CLKS

  Array initializer for all supported clock sources of I2C.

SOC_LP_I2C_CLKS

  Array initializer for all supported clock sources of LP_I2C.

SOC_SPI_CLKS

  Array initializer for all supported clock sources of SPI.

SOC_PSRAM_CLKS

  Array initializer for all supported clock sources of PSRAM.

SOC_FLASH_CLKS

  Array initializer for all supported clock sources of FLASH.

SOC_ISP_CLKS

  Array initializer for all supported clock sources of ISP.

SOC_SDM_CLKS

  Array initializer for all supported clock sources of SDM.

SOC_GLITCH_FILTER_CLKS

  Array initializer for all supported clock sources of Glitch Filter.

SOC_ANA_CMPR_CLKS

  Array initializer for all supported clock sources of Analog Comparator.

SOC_TWAI_CLKS

  Array initializer for all supported clock sources of TWAI.

SOC_ADC_DIGI_CLKS

  Array initializer for all supported clock sources of ADC digital controller.

SOC_ADC_RTC_CLKS

  Array initializer for all supported clock sources of ADC RTC controller.

SOC_MWDT_CLKS

  Array initializer for all supported clock sources of MWDT.

SOC_LEDC_CLKS

  Array initializer for all supported clock sources of LEDC.

SOC_PARLIO_CLKS

  Array initializer for all supported clock sources of PARLIO.

SOC_SDMMC_CLKS

  Array initializer for all supported clock sources of SDMMC.

SOC_TEMP_SENSOR_CLKS

  Array initializer for all supported clock sources of Temperature Sensor.

### Enumerations

enum soc_root_clk_t

  Root clock.

  Values:

  enumerator SOC_ROOT_CLK_INT_RC_FAST

    Internal 17.5MHz RC oscillator

  enumerator SOC_ROOT_CLK_INT_RC_SLOW

    Internal 136kHz RC oscillator

  enumerator SOC_ROOT_CLK_EXT_XTAL

    External 40MHz crystal

  enumerator SOC_ROOT_CLK_EXT_XTAL32K

    External 32kHz crystal

  enumerator SOC_ROOT_CLK_INT_RC32K

    Internal 32kHz RC oscillator

  enumerator SOC_ROOT_CLK_EXT_OSC_SLOW

    External slow clock signal at pin1

enum soc_cpu_clk_src_t

  CPU_CLK mux inputs, which are the supported clock sources for the CPU_CLK.

  Note

  Enum values are matched with the register field values on purpose

  Values:

  enumerator SOC_CPU_CLK_SRC_XTAL

    Select XTAL_CLK as CPU_CLK source

  enumerator SOC_CPU_CLK_SRC_CPLL

    Select CPLL_CLK as CPU_CLK source (CPLL_CLK is the output of 40MHz crystal oscillator frequency multiplier, can be 320/360/400MHz)

  enumerator SOC_CPU_CLK_SRC_PLL

    Alias name for `SOC_CPU_CLK_SRC_CPLL`

  enumerator SOC_CPU_CLK_SRC_RC_FAST

    Select RC_FAST_CLK as CPU_CLK source

  enumerator SOC_CPU_CLK_SRC_INVALID

    Invalid CPU_CLK source

enum soc_rtc_slow_clk_src_t

  RTC_SLOW_CLK mux inputs, which are the supported clock sources for the RTC_SLOW_CLK.

  Note

  Enum values are matched with the register field values on purpose

  Values:

  enumerator SOC_RTC_SLOW_CLK_SRC_RC_SLOW

    Select RC_SLOW_CLK as RTC_SLOW_CLK source

  enumerator SOC_RTC_SLOW_CLK_SRC_XTAL32K

    Select XTAL32K_CLK as RTC_SLOW_CLK source

  enumerator SOC_RTC_SLOW_CLK_SRC_RC32K

    Select RC32K_CLK as RTC_SLOW_CLK source

  enumerator SOC_RTC_SLOW_CLK_SRC_INVALID

    Invalid RTC_SLOW_CLK source

enum soc_rtc_fast_clk_src_t

  RTC_FAST_CLK mux inputs, which are the supported clock sources for the RTC_FAST_CLK.

  Note

  Enum values are matched with the register field values on purpose

  Values:

  enumerator SOC_RTC_FAST_CLK_SRC_RC_FAST

    Select RC_FAST_CLK as RTC_FAST_CLK source

  enumerator SOC_RTC_FAST_CLK_SRC_XTAL

    Select XTAL_CLK as RTC_FAST_CLK source

  enumerator SOC_RTC_FAST_CLK_SRC_XTAL_DIV

    Alias name for `SOC_RTC_FAST_CLK_SRC_XTAL`

  enumerator SOC_RTC_FAST_CLK_SRC_LP_PLL

    Select LP_PLL_CLK as RTC_FAST_CLK source (LP_PLL_CLK is a 8MHz clock sourced from RC32K or XTAL32K)

  enumerator SOC_RTC_FAST_CLK_SRC_INVALID

    Invalid RTC_FAST_CLK source

enum soc_lp_pll_clk_src_t

  LP_PLL_CLK mux inputs, which are the supported clock sources for the LP_PLL_CLK.

  Note

  Enum values are matched with the register field values on purpose

  Values:

  enumerator SOC_LP_PLL_CLK_SRC_RC32K

    Select RC32K_CLK as LP_PLL_CLK source

  enumerator SOC_LP_PLL_CLK_SRC_XTAL32K

    Select XTAL32K_CLK as LP_PLL_CLK source

  enumerator SOC_LP_PLL_CLK_SRC_INVALID

    Invalid LP_PLL_CLK source

enum soc_xtal_freq_t

  Possible main XTAL frequency options on the target.

  Note

  Enum values equal to the frequency value in MHz

  Note

  Not all frequency values listed here are supported in IDF. Please check SOC_XTAL_SUPPORT_XXX in soc_caps.h for the supported ones.

  Values:

  enumerator SOC_XTAL_FREQ_40M

    40MHz XTAL

enum soc_module_clk_t

  Supported clock sources for modules (CPU, peripherals, RTC, etc.)

  Note

  enum starts from 1, to save 0 for special purpose

  Values:

  enumerator SOC_MOD_CLK_CPU

    CPU_CLK can be sourced from XTAL, CPLL, or RC_FAST by configuring soc_cpu_clk_src_t

  enumerator SOC_MOD_CLK_RTC_FAST

    RTC_FAST_CLK can be sourced from XTAL, RC_FAST, or LP_PLL by configuring soc_rtc_fast_clk_src_t

  enumerator SOC_MOD_CLK_RTC_SLOW

    RTC_SLOW_CLK can be sourced from RC_SLOW, XTAL32K, or RC32K by configuring soc_rtc_slow_clk_src_t

  enumerator SOC_MOD_CLK_PLL_F20M

    PLL_F20M_CLK is derived from SPLL (clock gating + default divider 24), its default frequency is 20MHz

  enumerator SOC_MOD_CLK_PLL_F25M

    PLL_F25M_CLK is derived from MPLL (clock gating + configurable divider), it will have a frequency of 25MHz

  enumerator SOC_MOD_CLK_PLL_F50M

    PLL_F50M_CLK is derived from MPLL (clock gating + configurable divider 10), it will have a frequency of 50MHz

  enumerator SOC_MOD_CLK_PLL_F80M

    PLL_F80M_CLK is derived from SPLL (clock gating + default divider 6), its default frequency is 80MHz

  enumerator SOC_MOD_CLK_PLL_F160M

    PLL_F160M_CLK is derived from SPLL (clock gating + default divider 3), its default frequency is 160MHz

  enumerator SOC_MOD_CLK_PLL_F240M

    PLL_F240M_CLK is derived from SPLL (clock gating + default divider 2), its default frequency is 240MHz

  enumerator SOC_MOD_CLK_CPLL

    CPLL is from 40MHz XTAL oscillator frequency multipliers

  enumerator SOC_MOD_CLK_SPLL

    SPLL is from 40MHz XTAL oscillator frequency multipliers, its default frequency is 480MHz

  enumerator SOC_MOD_CLK_MPLL

    MPLL is from 40MHz XTAL oscillator frequency multipliers

  enumerator SOC_MOD_CLK_XTAL32K

    XTAL32K_CLK comes from the external 32kHz crystal, passing a clock gating to the peripherals

  enumerator SOC_MOD_CLK_RC_FAST

    RC_FAST_CLK comes from the internal 20MHz rc oscillator, passing a clock gating to the peripherals

  enumerator SOC_MOD_CLK_XTAL

    XTAL_CLK comes from the external 40MHz crystal

  enumerator SOC_MOD_CLK_APLL

    Audio PLL is sourced from PLL, and its frequency is configurable through APLL configuration registers

  enumerator SOC_MOD_CLK_XTAL_D2

    XTAL_D2_CLK comes from the external 40MHz crystal, passing a div of 2 to the LP peripherals

  enumerator SOC_MOD_CLK_LP_PLL

    LP_PLL is from 32kHz XTAL oscillator frequency multipliers, it has a fixed frequency of 8MHz

  enumerator SOC_MOD_CLK_LP_DYN_FAST

    LP_DYN_FAST can be derived from RTC_SLOW_CLK or RTC_FAST_CLK depending on the chip’s power mode: in active mode, select RTC_FAST_CLK as the clock source; in light/deep sleep mode, select RTC_SLOW_CLK as the clock source

  enumerator SOC_MOD_CLK_LP_PERI

    LP_PERI_CLK is derived from LP_DYN_FAST (configurable divider)

  enumerator SOC_MOD_CLK_INVALID

    Indication of the end of the available module clock sources

enum soc_periph_systimer_clk_src_t

  Type of SYSTIMER clock source.

  Values:

  enumerator SYSTIMER_CLK_SRC_XTAL

    SYSTIMER source clock is XTAL

  enumerator SYSTIMER_CLK_SRC_RC_FAST

    SYSTIMER source clock is RC_FAST

  enumerator SYSTIMER_CLK_SRC_DEFAULT

    SYSTIMER source clock default choice is XTAL

enum soc_periph_gptimer_clk_src_t

  Type of GPTimer clock source.

  Values:

  enumerator GPTIMER_CLK_SRC_PLL_F80M

    Select PLL_F80M as the source clock

  enumerator GPTIMER_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator GPTIMER_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator GPTIMER_CLK_SRC_DEFAULT

    Select PLL_F80M as the default choice

enum soc_periph_tg_clk_src_legacy_t

  Type of Timer Group clock source, reserved for the legacy timer group driver.

  Values:

  enumerator TIMER_SRC_CLK_PLL_F80M

    Timer group clock source is PLL_F80M

  enumerator TIMER_SRC_CLK_XTAL

    Timer group clock source is XTAL

  enumerator TIMER_SRC_CLK_DEFAULT

    Timer group clock source default choice is PLL_F80M

enum soc_periph_rmt_clk_src_t

  Type of RMT clock source.

  Values:

  enumerator RMT_CLK_SRC_PLL_F80M

    Select PLL_F80M as the source clock

  enumerator RMT_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator RMT_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator RMT_CLK_SRC_DEFAULT

    Select PLL_F80M as the default choice

enum soc_periph_rmt_clk_src_legacy_t

  Type of RMT clock source, reserved for the legacy RMT driver.

  Values:

  enumerator RMT_BASECLK_PLL_F80M

    RMT source clock is PLL_F80M

  enumerator RMT_BASECLK_XTAL

    RMT source clock is XTAL

  enumerator RMT_BASECLK_DEFAULT

    RMT source clock default choice is PLL_F80M

enum soc_periph_uart_clk_src_legacy_t

  Type of UART clock source, reserved for the legacy UART driver.

  Values:

  enumerator UART_SCLK_PLL_F80M

    UART source clock is PLL_F80M

  enumerator UART_SCLK_RTC

    UART source clock is RC_FAST

  enumerator UART_SCLK_XTAL

    UART source clock is XTAL

  enumerator UART_SCLK_DEFAULT

    UART source clock default choice is PLL_F80M

enum soc_periph_lp_uart_clk_src_t

  Type of LP_UART clock source.

  Values:

  enumerator LP_UART_SCLK_LP_FAST

    LP_UART source clock is LP(RTC)_FAST

  enumerator LP_UART_SCLK_XTAL_D2

    LP_UART source clock is XTAL_D2

  enumerator LP_UART_SCLK_DEFAULT

    LP_UART source clock default choice is LP(RTC)_FAST

enum soc_periph_mcpwm_timer_clk_src_t

  Type of MCPWM timer clock source.

  Values:

  enumerator MCPWM_TIMER_CLK_SRC_PLL160M

    Select PLL_F160M as the source clock

  enumerator MCPWM_TIMER_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator MCPWM_TIMER_CLK_SRC_DEFAULT

    Select PLL_F160M as the default choice

enum soc_periph_mcpwm_capture_clk_src_t

  Type of MCPWM capture clock source.

  Values:

  enumerator MCPWM_CAPTURE_CLK_SRC_PLL160M

    Select PLL_F160M as the source clock

  enumerator MCPWM_CAPTURE_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator MCPWM_CAPTURE_CLK_SRC_DEFAULT

    Select PLL_F160M as the default choice

enum soc_periph_mcpwm_carrier_clk_src_t

  Type of MCPWM carrier clock source.

  Values:

  enumerator MCPWM_CARRIER_CLK_SRC_PLL160M

    Select PLL_F160M as the source clock

  enumerator MCPWM_CARRIER_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator MCPWM_CARRIER_CLK_SRC_DEFAULT

    Select PLL_F160M as the default choice

enum soc_periph_i2s_clk_src_t

  I2S clock source enum.

  Values:

  enumerator I2S_CLK_SRC_DEFAULT

    Select XTAL as the default source clock

  enumerator I2S_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator I2S_CLK_SRC_APLL

    Select APLL as the source clock

  enumerator I2S_CLK_SRC_EXTERNAL

    Select external clock as source clock

enum soc_periph_lp_i2s_clk_src_t

  LP I2S clock source enum.

  Values:

  enumerator LP_I2S_CLK_SRC_DEFAULT

    Select LP_PERI as the default source clock

  enumerator LP_I2S_CLK_SRC_LP_PERI

    Select LP_PERI as the source clock

  enumerator LP_I2S_CLK_SRC_XTAL_D2

    LP_I2S source clock is XTAL_D2

enum soc_periph_lcd_clk_src_t

  Type of LCD clock source.

  Values:

  enumerator LCD_CLK_SRC_PLL160M

    Select PLL_F160M as the source clock

  enumerator LCD_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator LCD_CLK_SRC_APLL

    Select APLL as the source clock

  enumerator LCD_CLK_SRC_DEFAULT

    Select PLL_F160M as the default choice

enum soc_periph_cam_clk_src_t

  Type of CAM clock source.

  Values:

  enumerator CAM_CLK_SRC_PLL160M

    Select PLL_F160M as the source clock

  enumerator CAM_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator CAM_CLK_SRC_APLL

    Select APLL as the source clock

  enumerator CAM_CLK_SRC_DEFAULT

    Select PLL_F160M as the default choice

enum soc_periph_mipi_csi_phy_clk_src_t

  Type of MIPI CSI PHY clock source.

  Values:

  enumerator MIPI_CSI_PHY_CLK_SRC_RC_FAST

    Select RC_FAST as MIPI CSI PHY source clock

  enumerator MIPI_CSI_PHY_CLK_SRC_PLL_F25M

    Select PLL_F25M as MIPI CSI PHY source clock

  enumerator MIPI_CSI_PHY_CLK_SRC_PLL_F20M

    Select PLL_F20M as MIPI CSI PHY source clock

  enumerator MIPI_CSI_PHY_CLK_SRC_DEFAULT

    Select PLL_F20M as default clock

enum soc_periph_mipi_dsi_dpi_clk_src_t

  Type of MIPI DSI DPI clock source.

  Values:

  enumerator MIPI_DSI_DPI_CLK_SRC_XTAL

    Select XTAL as MIPI DSI DPI source clock

  enumerator MIPI_DSI_DPI_CLK_SRC_PLL_F160M

    Select PLL_F160M as MIPI DSI DPI source clock

  enumerator MIPI_DSI_DPI_CLK_SRC_PLL_F240M

    Select PLL_F240M as MIPI DSI DPI source clock

  enumerator MIPI_DSI_DPI_CLK_SRC_DEFAULT

    Select PLL_F240M as default clock

enum soc_periph_mipi_dsi_phy_clk_src_t

  Type of MIPI DSI PHY clock source.

  Values:

  enumerator MIPI_DSI_PHY_CLK_SRC_RC_FAST

    Select RC_FAST as MIPI DSI PHY source clock

  enumerator MIPI_DSI_PHY_CLK_SRC_PLL_F25M

    Select PLL_F25M as MIPI DSI PHY source clock

  enumerator MIPI_DSI_PHY_CLK_SRC_PLL_F20M

    Select PLL_F20M as MIPI DSI PHY source clock

  enumerator MIPI_DSI_PHY_CLK_SRC_DEFAULT

    Select PLL_F20M as default clock

enum soc_periph_i2c_clk_src_t

  Type of I2C clock source.

  Values:

  enumerator I2C_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator I2C_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator I2C_CLK_SRC_DEFAULT

    Select XTAL as the default source clock

enum soc_periph_lp_i2c_clk_src_t

  Type of LP_I2C clock source.

  Values:

  enumerator LP_I2C_SCLK_LP_FAST

    LP_I2C source clock is RTC_FAST

  enumerator LP_I2C_SCLK_XTAL_D2

    LP_I2C source clock is XTAL_D2

  enumerator LP_I2C_SCLK_DEFAULT

    LP_I2C source clock default choice is RTC_FAST

enum soc_periph_spi_clk_src_t

  Type of SPI clock source.

  Values:

  enumerator SPI_CLK_SRC_XTAL

    Select XTAL as SPI source clock

  enumerator SPI_CLK_SRC_RC_FAST

    Select RC_FAST_20M as SPI source clock

  enumerator SPI_CLK_SRC_SPLL

    Select SPLL as SPI source clock

  enumerator SPI_CLK_SRC_DEFAULT

    Select SPLL as SPI source clock

enum soc_periph_psram_clk_src_t

  Type of PSRAM clock source.

  Values:

  enumerator PSRAM_CLK_SRC_DEFAULT

    Select SOC_MOD_CLK_SPLL as PSRAM source clock

  enumerator PSRAM_CLK_SRC_XTAL

    Select SOC_MOD_CLK_XTAL as PSRAM source clock

  enumerator PSRAM_CLK_SRC_CPLL

    Select SOC_MOD_CLK_CPLL as PSRAM source clock

  enumerator PSRAM_CLK_SRC_SPLL

    Select SOC_MOD_CLK_SPLL as PSRAM source clock

  enumerator PSRAM_CLK_SRC_MPLL

    Select SOC_MOD_CLK_MPLL as PSRAM source clock

enum soc_periph_flash_clk_src_t

  Type of FLASH clock source.

  Values:

  enumerator FLASH_CLK_SRC_DEFAULT

    Select SOC_MOD_CLK_SPLL as FLASH source clock

  enumerator FLASH_CLK_SRC_XTAL

    Select SOC_MOD_CLK_XTAL as FLASH source clock

  enumerator FLASH_CLK_SRC_CPLL

    Select SOC_MOD_CLK_CPLL as FLASH source clock

  enumerator FLASH_CLK_SRC_SPLL

    Select SOC_MOD_CLK_SPLL as FLASH source clock

enum soc_periph_isp_clk_src_t

  Type of ISP clock source.

  Values:

  enumerator ISP_CLK_SRC_DEFAULT

    Select SOC_MOD_CLK_PLL_F160M as ISP source clock

  enumerator ISP_CLK_SRC_XTAL

    Select SOC_MOD_CLK_XTAL as ISP source clock

  enumerator ISP_CLK_SRC_PLL160

    Select SOC_MOD_CLK_PLL_F160M as ISP source clock

  enumerator ISP_CLK_SRC_PLL240

    Select SOC_MOD_CLK_PLL_F240M as ISP source clock

enum soc_periph_sdm_clk_src_t

  Sigma Delta Modulator clock source.

  Values:

  enumerator SDM_CLK_SRC_XTAL

    Select XTAL clock as the source clock

  enumerator SDM_CLK_SRC_PLL_F80M

    Select PLL_F80M clock as the source clock

  enumerator SDM_CLK_SRC_DEFAULT

    Select PLL_F80M clock as the default clock choice

enum soc_periph_glitch_filter_clk_src_t

  Glitch filter clock source.

  Values:

  enumerator GLITCH_FILTER_CLK_SRC_XTAL

    Select XTAL clock as the source clock

  enumerator GLITCH_FILTER_CLK_SRC_PLL_F80M

    Select PLL_F80M clock as the source clock

  enumerator GLITCH_FILTER_CLK_SRC_DEFAULT

    Select PLL_F80M clock as the default clock choice

enum soc_periph_ana_cmpr_clk_src_t

  Analog Comparator clock source.

  Values:

  enumerator ANA_CMPR_CLK_SRC_XTAL

    Select XTAL clock as the source clock

  enumerator ANA_CMPR_CLK_SRC_PLL_F80M

    Select PLL_F80M clock as the source clock

  enumerator ANA_CMPR_CLK_SRC_DEFAULT

    Select PLL_F80M as the default clock choice

enum soc_periph_twai_clk_src_t

  TWAI clock source.

  Values:

  enumerator TWAI_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator TWAI_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator TWAI_CLK_SRC_DEFAULT

    Select XTAL as the default clock choice

enum soc_periph_adc_digi_clk_src_t

  ADC digital controller clock source.

  Values:

  enumerator ADC_DIGI_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator ADC_DIGI_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator ADC_DIGI_CLK_SRC_PLL_F80M

    Select PLL_F80M as the source clock

  enumerator ADC_DIGI_CLK_SRC_DEFAULT

    Select PLL_F80M as the default clock choice

enum soc_periph_adc_rtc_clk_src_t

  ADC RTC controller clock source.

  Values:

  enumerator ADC_RTC_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator ADC_RTC_CLK_SRC_DEFAULT

    Select RC_FAST as the default clock choice

enum soc_periph_mwdt_clk_src_t

  MWDT clock source.

  Values:

  enumerator MWDT_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator MWDT_CLK_SRC_PLL_F80M

    Select PLL fixed 80 MHz as the source clock

  enumerator MWDT_CLK_SRC_RC_FAST

    Select RTC fast as the source clock

  enumerator MWDT_CLK_SRC_DEFAULT

    Select XTAL 40 MHz as the default clock choice

enum soc_periph_ledc_clk_src_legacy_t

  Type of LEDC clock source, reserved for the legacy LEDC driver.

  Values:

  enumerator LEDC_AUTO_CLK

    LEDC source clock will be automatically selected based on the giving resolution and duty parameter when init the timer

  enumerator LEDC_USE_XTAL_CLK

    Select XTAL as the source clock

  enumerator LEDC_USE_PLL_DIV_CLK

    Select PLL_F80M clock as the source clock

  enumerator LEDC_USE_RC_FAST_CLK

    Select RC_FAST as the source clock

enum soc_periph_parlio_clk_src_t

  PARLIO clock source.

  Values:

  enumerator PARLIO_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator PARLIO_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator PARLIO_CLK_SRC_PLL_F160M

    Select PLL_F160M as the source clock

  enumerator PARLIO_CLK_SRC_EXTERNAL

    Select EXTERNAL clock as the source clock

  enumerator PARLIO_CLK_SRC_DEFAULT

    Select PLL_F160M as the default clock choice

enum soc_periph_sdmmc_clk_src_t

  Type of SDMMC clock source.

  Values:

  enumerator SDMMC_CLK_SRC_DEFAULT

    Select PLL_160M as the default choice

  enumerator SDMMC_CLK_SRC_PLL160M

    Select PLL_160M as the source clock

enum soc_periph_temperature_sensor_clk_src_t

  Type of Temp Sensor clock source.

  Values:

  enumerator TEMPERATURE_SENSOR_CLK_SRC_LP_PERI

    Select LP_PERI as the source clock

  enumerator TEMPERATURE_SENSOR_CLK_SRC_DEFAULT

    Select LP_PERI as the default choice

enum soc_clkout_sig_id_t

  Values:

  enumerator CLKOUT_SIG_MPLL

    MPLL is from 40MHz XTAL oscillator frequency multipliers

  enumerator CLKOUT_SIG_SPLL

    SPLL is from 40MHz XTAL oscillator frequency multipliers, its default frequency is 480MHz

  enumerator CLKOUT_SIG_CPLL

    CPLL_CLK is the output of 40MHz crystal oscillator frequency multiplier, can be 320/360/400MHz

  enumerator CLKOUT_SIG_XTAL

    External 40MHz crystal

  enumerator CLKOUT_SIG_RC_FAST

    Internal 17.5MHz RC oscillator

  enumerator CLKOUT_SIG_RC_SLOW

    Internal 136kHz RC oscillator

  enumerator CLKOUT_SIG_RC_32K

    Internal 32kHz RC oscillator

  enumerator CLKOUT_SIG_XTAL32K

    External 32kHz crystal clock

  enumerator CLKOUT_SIG_I2S0

    I2S0 clock, depends on the i2s driver configuration

  enumerator CLKOUT_SIG_I2S1

    I2S1 clock, depends on the i2s driver configuration

  enumerator CLKOUT_SIG_I2S2

    I2S2 clock, depends on the i2s driver configuration

  enumerator CLKOUT_SIG_CPU

    CPU clock

  enumerator CLKOUT_SIG_MEM

    MEM clock

  enumerator CLKOUT_SIG_SYS

    SYS clock

  enumerator CLKOUT_SIG_APB

    APB clock

  enumerator CLKOUT_SIG_PLL_F80M

    From PLL, usually be 80MHz

  enumerator CLKOUT_SIG_INVALID

### Header File

- components/esp_hw_support/include/esp_clk_tree.h

- This header file can be included with:

  >     #include "esp_clk_tree.h"

### Functions

esp_err_t esp_clk_tree_src_get_freq_hz(soc_module_clk_t clk_src, esp_clk_tree_src_freq_precision_t precision, uint32_t *freq_value)

  Get frequency of module clock source.

  Parameters:

    - clk_src -- [in] Clock source available to modules, in soc_module_clk_t

    - precision -- [in] Degree of precision, one of esp_clk_tree_src_freq_precision_t values This arg only applies to the clock sources that their frequencies can vary: SOC_MOD_CLK_RTC_FAST, SOC_MOD_CLK_RTC_SLOW, SOC_MOD_CLK_RC_FAST, SOC_MOD_CLK_RC_FAST_D256, SOC_MOD_CLK_XTAL32K For other clock sources, this field is ignored.

    - freq_value -- [out] Frequency of the clock source, in Hz

  Returns:

    - ESP_OK Success

    - ESP_ERR_INVALID_ARG Parameter error

    - ESP_FAIL Calibration failed

### Enumerations

enum esp_clk_tree_src_freq_precision_t

  Degree of precision of frequency value to be returned by esp_clk_tree_src_get_freq_hz()

  Values:

  enumerator ESP_CLK_TREE_SRC_FREQ_PRECISION_CACHED
  enumerator ESP_CLK_TREE_SRC_FREQ_PRECISION_APPROX
  enumerator ESP_CLK_TREE_SRC_FREQ_PRECISION_EXACT
  enumerator ESP_CLK_TREE_SRC_FREQ_PRECISION_INVALID

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