# 时钟树

[English]

ESP32-S31 的时钟子系统用于从一系列根时钟中提取并分配系统/模块时钟。时钟树驱动程序负责维护系统时钟的基本功能，并管理模块时钟间的复杂关系。

本文档首先介绍了根时钟和模块时钟，随后介绍了可供用户调用的时钟树 API，调用这些 API，可以监测模块时钟的运行状态。

## 简介

本节列出了 ESP32-S31 支持的根时钟和模块时钟的定义，这些定义通常用于驱动程序配置，有助于为外设选择合适的时钟源。

### 根时钟

根时钟会产生可靠的时钟信号，经各种门、复用器、分频器或倍频器传递，这些时钟信号最终成为 CPU 内核、Wi-Fi、蓝牙、RTC 及外设等功能模块的时钟源。

ESP32-S31 的根时钟列在 `soc_root_clk_t` 中：

> - 内部 17.5 MHz RC 振荡器 (RC_FAST)

>   > 此 RC 振荡器可产生约 17.5 MHz 的时钟信号输出，标识为 `RC_FAST_CLK`。

>   > 在运行时，通过校准，可以计算 `RC_FAST_CLK` 的实际频率。

> - 外部 40 MHz 晶振 (XTAL)

> - 内部 136 kHz RC 振荡器 (RC_SLOW)

>   > 此 RC 振荡器产生约 136 kHz 的时钟信号输出，标识为 `RC_SLOW_CLK`。在运行时，通过校准，可以计算该时钟信号的实际频率。

> - 外部 32 kHz 晶振 - 可选 (XTAL32K)

>   > `XTAL32K_CLK` 的时钟源是连接到 `XTAL_32K_P` 和 `XTAL_32K_N` 管脚的 32 kHz 晶振。

>   > 通过校准，可以计算 `XTAL32K_CLK` 的实际频率。

与晶振产生的信号相比，从 RC 振荡器电路产生的信号通常精度较低，且容易受环境影响。因此，ESP32-S31 为 `RTC_SLOW_CLK` 提供了几种时钟源选项，可以根据对系统时间精度和对功耗的要求选择。更多详情，请参阅 RTC 定时器时钟源。

### 模块时钟

ESP32-S31 的可用模块时钟在 `soc_module_clk_t` 中列出，每个模块时钟都有其唯一 ID。查阅文档中的枚举值，即可获取各模块时钟的详细信息。

## 使用 API

时钟树驱动程序提供了一个一体化接口，可以获取模块时钟的频率，即 `esp_clk_tree_src_get_freq_hz()`。通过该函数，你可以在任何时刻，通过提供时钟名称 `soc_module_clk_t` 和指定返回频率值的精度级别 `esp_clk_tree_src_freq_precision_t`，获取时钟频率。

## API 参考

### Header File

- components/soc/esp32s31/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_XTAL32K_FREQ_APPROX

  Approximate XTAL32K_CLK frequency in Hz

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_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_LEDC_CLKS

  Array initializer for all supported clock sources of LEDC.

SOC_LEDC_CLK_STRS

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_SDMMC_CLKS

  Array initializer for all supported clock sources of SDMMC.

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_MWDT_CLKS

  Array initializer for all supported clock sources of MWDT.

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_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

  I2S clock source.

SOC_PARLIO_CLKS

  Array initializer for all supported clock sources of PARLIO.

SOC_CORDIC_CLKS

  Array initializer for all supported clock sources of CORDIC.

SOC_PCNT_CLKS

  Array initializer for all supported clock sources of PCNT.

SOC_ADC_DIGI_CLKS

  Array initializer for all supported clock sources of ADC.

SOC_TEMP_SENSOR_CLKS

  Array initializer for all supported clock sources of Temperature Sensor.

SOC_EMAC_OUT_CLK

  Array initializer for all supported clock sources of EMAC clock output.

SOC_EMAC_REF_PHY_CLK

  Array initializer for all supported clock sources of EMAC REF_PHY clock output.

SOC_EMAC_PTP_CLK

  Array initializer for all supported clock sources of EMAC PTP.

### 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

enum soc_root_clk_circuit_t

  ROOT clock circuit, which requires explicitly enabling the targeting circuit to use.

  Values:

  enumerator SOC_ROOT_CIRCUIT_CLK_BBPLL

    BBPLL_CLK is the output of the BBPLL generator circuit

  enumerator SOC_ROOT_CIRCUIT_CLK_CPLL

    CPLL_CLK is the output of the CPLL generator circuit

  enumerator SOC_ROOT_CIRCUIT_CLK_MPLL

    MPLL_CLK is the output of the MPLL generator circuit

  enumerator SOC_ROOT_CIRCUIT_CLK_APLL

    APLL_CLK is the output of the APLL generator circuit

enum soc_cpu_clk_src_t

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

  备注

  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 320MHz)

  enumerator SOC_CPU_CLK_SRC_RC_FAST

    Select RC_FAST_CLK as CPU_CLK source

  enumerator SOC_CPU_CLK_SRC_PLL_F240M

    Select PLL_F240M_CLK as CPU_CLK source (PLL_F240M_CLK is derived from BBPLL (480MHz), which is the output of the main crystal oscillator frequency multiplier)

  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.

  备注

  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_INVALID

    Invalid RTC_SLOW_CLK source

  enumerator SOC_RTC_SLOW_CLK_SRC_DEFAULT

    RC_SLOW_CLK is the default clock source for RTC_SLOW_CLK

enum soc_rtc_fast_clk_src_t

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

  备注

  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_INVALID

    Invalid RTC_FAST_CLK source

  enumerator SOC_RTC_FAST_CLK_SRC_DEFAULT

    XTAL_CLK is the default clock source for RTC_FAST_CLK

enum soc_xtal_freq_t

  Possible main XTAL frequency options on the target.

  备注

  Enum values equal to the frequency value in MHz

  备注

  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.)

  备注

  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, or RC_FAST 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_SYS

    SYS_CLK is the system clock, derived from SOC_CLK clock source

  enumerator SOC_MOD_CLK_PLL_F20M

    PLL_F20M_CLK is derived from BBPLL (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 C/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 BBPLL (clock gating + default divider 6), its default frequency is 80MHz

  enumerator SOC_MOD_CLK_PLL_F160M

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

  enumerator SOC_MOD_CLK_PLL_F240M

    PLL_F240M_CLK is derived from BBPLL (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_BBPLL

    BBPLL 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_APB

    APB_CLK is highly dependent on the CPU_CLK source

  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_DYN_FAST

    LP_DYN_FAST can be derived from RTC_SLOW_CLK or RTC_FAST_CLK depending on the chip’s power mode: Only in LP_SLEEP mode, select RTC_SLOW_CLK as the clock source; In other non-LP_SLEEP mode, select RTC_FAST_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_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_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_etm_clk_src_t

  Values:

  enumerator ETM_CLK_SRC_PLL_F80M

    Select PLL_F80M as the source clock

  enumerator ETM_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator ETM_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator ETM_CLK_SRC_DEFAULT

    Select PLL_F80M as the default choice

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_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_RC_FAST

    LP_UART source clock is FOSC

  enumerator LP_UART_SCLK_XTAL

    LP_UART source clock is XTAL

  enumerator LP_UART_SCLK_DEFAULT

    LP_UART source clock default choice is FOSC

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_PLL_DIV_CLK

    Select PLL_F80M clock as the source clock

  enumerator LEDC_USE_RC_FAST_CLK

    Select RC_FAST as the source clock

  enumerator LEDC_USE_XTAL_CLK

    Select XTAL as the source 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 clock choice

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

    LP_I2C source clock is XTAL

  enumerator LP_I2C_SCLK_DEFAULT

    LP_I2C source clock default choice is RTC_FAST

enum soc_periph_sdmmc_clk_src_t

  Type of SDMMC clock source.

  Values:

  enumerator SDMMC_CLK_SRC_DEFAULT

    Select MPLL as the default choice

  enumerator SDMMC_CLK_SRC_MPLL

    Select MPLL as the source clock

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_BBPLL

    Select BBPLL as SPI source clock

  enumerator SPI_CLK_SRC_DEFAULT

    Select BBPLL as default source clock

enum soc_periph_psram_clk_src_t

  Type of PSRAM clock source.

  Values:

  enumerator PSRAM_CLK_SRC_DEFAULT

    Select SOC_MOD_CLK_MPLL 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_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_BBPLL 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_BBPLL

    Select SOC_MOD_CLK_BBPLL as FLASH source clock

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_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

  Type of Analog Comparator clock source.

  Values:

  enumerator ANA_CMPR_CLK_SRC_XTAL

    Select XTAL clock as the source clock

  enumerator ANA_CMPR_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator ANA_CMPR_CLK_SRC_PLL_F80M

    Select PLL_F80M 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_PLL_F80M

    Select PLL_F80M as the source clock

  enumerator TWAI_CLK_SRC_DEFAULT

    Select PLL_F80M as the default clock choice

enum soc_periph_mcpwm_timer_clk_src_t

  Type of MCPWM timer clock source.

  Values:

  enumerator MCPWM_TIMER_CLK_SRC_XTAL

    Select XTAL as the source clock

  enumerator MCPWM_TIMER_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator MCPWM_TIMER_CLK_SRC_PLL160M

    Select PLL_F160M 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_XTAL

    Select XTAL as the source clock

  enumerator MCPWM_CAPTURE_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator MCPWM_CAPTURE_CLK_SRC_PLL160M

    Select PLL_F160M 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_XTAL

    Select XTAL as the source clock

  enumerator MCPWM_CARRIER_CLK_SRC_RC_FAST

    Select RC_FAST as the source clock

  enumerator MCPWM_CARRIER_CLK_SRC_PLL160M

    Select PLL_F160M 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.

  备注

  Enum values are matched with the register field values on purpose

  Values:

  enumerator I2S_CLK_SRC_DEFAULT

    Auto select maximum clock source as 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_RC_FAST

    Select RC_FAST as the source clock

  enumerator I2S_CLK_SRC_EXTERNAL

    Select external clock as 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_clkout_sig_id_t

  Values:

  enumerator CLKOUT_SIG_MPLL_500M

    MPLL output at 500MHz

  enumerator CLKOUT_SIG_BBPLL_480M

    BBPLL output at 480MHz

  enumerator CLKOUT_SIG_CPLL_300M

    CPLL output at 300MHz

  enumerator CLKOUT_SIG_XTAL_40M

    Main crystal clock at 40MHz

  enumerator CLKOUT_SIG_FOSC_20M

    Fast RC oscillator ; nominally ~20MHz

  enumerator CLKOUT_SIG_SOSC_600KD4

    Slow RC oscillator ; ~150kHz before RTC divider path, used for RTC slow timing

  enumerator CLKOUT_SIG_RC_32K

    Internal ~32kHz RC oscillator output (low-precision; not recommended for applications)

  enumerator CLKOUT_SIG_XTAL_32K

    External 32kHz crystal clock (XTAL32K on XTAL_32K_P/N)

  enumerator CLKOUT_SIG_ANA_PLL_80M

    80MHz analog PLL

  enumerator CLKOUT_SIG_USB_OTGHS_PHYREF

    USB OTG HS PHY reference clock output for the high-speed PHY

  enumerator CLKOUT_SIG_USB_OTGHS_ULPI

    USB OTG HS ULPI interface clock output

  enumerator CLKOUT_SIG_MCPWM2

    MCPWM 2 module clock

  enumerator CLKOUT_SIG_MCPWM3

    MCPWM 3 module clock

  enumerator CLKOUT_SIG_CORE0_CLIC

    Core 0 clock

  enumerator CLKOUT_SIG_CORE1_CLIC

    Core 1 clock

  enumerator CLKOUT_SIG_AUDIO_PLL

    Audio PLL (APLL) output; frequency set via APLL configuration registers

  enumerator CLKOUT_SIG_PAD_I2S0_MCLK

    I2S0 master clock

  enumerator CLKOUT_SIG_PAD_I2S1_MCLK

    I2S1 master clock

  enumerator CLKOUT_SIG_USB_DEVICE_INTPHY

    Full-speed USB device internal PHY clock

  enumerator CLKOUT_SIG_PAD_UART0_SLP

    UART0 sleep pad clock

  enumerator CLKOUT_SIG_PAD_UART1_SLP

    UART1 sleep pad clock

  enumerator CLKOUT_SIG_PAD_UART2_SLP

    UART2 sleep pad clock

  enumerator CLKOUT_SIG_PAD_UART3_SLP

    UART3 sleep pad clock

  enumerator CLKOUT_SIG_USB_DEVICE_48M

    USB device 48MHz functional clock output

  enumerator CLKOUT_SIG_PAD_PARLIO_RX

    Parallel IO (PARLIO) RX clock

  enumerator CLKOUT_SIG_PAD_PARLIO_TX

    Parallel IO (PARLIO) TX clock

  enumerator CLKOUT_SIG_TCELL_CPU

    CPU domain clock

  enumerator CLKOUT_SIG_TCELL_MEM

    memory subsystem clock

  enumerator CLKOUT_SIG_TCELL_SYS

    system bus clock

  enumerator CLKOUT_SIG_TCELL_APB

    APB peripheral bus clock

  enumerator CLKOUT_SIG_FLASH_PLL

    MSPI flash PLL

  enumerator CLKOUT_SIG_FLASH_CORE

    MSPI flash controller core clock

  enumerator CLKOUT_SIG_PSRAM_PLL

    MSPI PSRAM PLL clock

  enumerator CLKOUT_SIG_PSRAM_CORE

    MSPI PSRAM controller core clock

  enumerator CLKOUT_SIG_ULPI_CLK_PAD_OUT

    ULPI clock forwarded to pad output

  enumerator CLKOUT_SIG_SDIO_SLF

    SDIO slave

  enumerator CLKOUT_SIG_SDIO_DRV

    sdio_drv_clk_o

  enumerator CLKOUT_SIG_SDIO_SAM

    sdio_sam_clk_o

  enumerator CLKOUT_SIG_I2C0

    I2C0 peripheral module clock

  enumerator CLKOUT_SIG_I2C1

    I2C1 peripheral module clock

  enumerator CLKOUT_SIG_I2S0_RX

    I2S0 rx clock

  enumerator CLKOUT_SIG_I2S0_TX

    I2S0 tx clock

  enumerator CLKOUT_SIG_I2S1_RX

    I2S1 rx clock

  enumerator CLKOUT_SIG_I2S1_TX

    I2S1 tx clock

  enumerator CLKOUT_SIG_LCD

    LCD controller module clock

  enumerator CLKOUT_SIG_UART0_SCLK

    UART0 source clock

  enumerator CLKOUT_SIG_UART0_FCLK

    UART0 functional clock

  enumerator CLKOUT_SIG_UART0_SLP

    UART0 sleep clock

  enumerator CLKOUT_SIG_UART1_SCLK

    UART1 source clock

  enumerator CLKOUT_SIG_UART1_FCLK

    UART1 functional clock

  enumerator CLKOUT_SIG_UART1_SLP

    UART1 sleep clock

  enumerator CLKOUT_SIG_UART2_SCLK

    UART2 source clock

  enumerator CLKOUT_SIG_UART2_FCLK

    UART2 functional clock

  enumerator CLKOUT_SIG_UART2_SLP

    UART2 sleep clock

  enumerator CLKOUT_SIG_UART3_SCLK

    UART3 source clock

  enumerator CLKOUT_SIG_UART3_FCLK

    UART3 functional clock

  enumerator CLKOUT_SIG_UART3_SLP

    UART3 sleep clock

  enumerator CLKOUT_SIG_CORDIC_CORE

    CORDIC accelerator core clock

  enumerator CLKOUT_SIG_ZERO_DET_CORE

    Zero-cross / zero-detection peripheral core clock

  enumerator CLKOUT_SIG_TWAI0

    TWAI0 module clock

  enumerator CLKOUT_SIG_TWAI1

    TWAI1 module clock

  enumerator CLKOUT_SIG_GPSPI2_HS

    SPI2 high-speed clock

  enumerator CLKOUT_SIG_GPSPI2_MST

    SPI2 master functional clock

  enumerator CLKOUT_SIG_GPSPI3_HS

    SPI3 high-speed clock

  enumerator CLKOUT_SIG_GPSPI3_MST

    SPI3 master functional clock

  enumerator CLKOUT_SIG_PARLIO_RX

    PARLIO RX clock

  enumerator CLKOUT_SIG_PARLIO_TX

    PARLIO TX clock

  enumerator CLKOUT_SIG_MCPWM0

    MCPWM0 module clock

  enumerator CLKOUT_SIG_MCPWM1

    MCPWM1 module clock

  enumerator CLKOUT_SIG_TIMERGRP0_T0

    Timer group 0, timer 0 module clock

  enumerator CLKOUT_SIG_TIMERGRP0_T1

    Timer group 0, timer 1 module clock

  enumerator CLKOUT_SIG_TIMERGRP0_WDT

    Timer group 0 watchdog module clock

  enumerator CLKOUT_SIG_TIMERGRP1_T0

    Timer group 1, timer 0 module clock

  enumerator CLKOUT_SIG_TIMERGRP1_T1

    Timer group 1, timer 1 module clock

  enumerator CLKOUT_SIG_TIMERGRP1_WDT

    Timer group 1 watchdog module clock

  enumerator CLKOUT_SIG_SYSTIMER

    System timer module clock

  enumerator CLKOUT_SIG_LEDC0

    LED PWM controller instance 0 module clock

  enumerator CLKOUT_SIG_RMT

    RMT peripheral module clock

  enumerator CLKOUT_SIG_ADC

    ADC module clock

  enumerator CLKOUT_SIG_ADC_SAR1

    SAR_ADC1 clock

  enumerator CLKOUT_SIG_ADC_SAR2

    SAR_ADC2 clock

  enumerator CLKOUT_SIG_ADC_SAR1_GCLK

    SAR_ADC1 GCLK

  enumerator CLKOUT_SIG_ADC_SAR2_GCLK

    SAR_ADC2 GCLK

  enumerator CLKOUT_SIG_PVT

    PVT module clock

  enumerator CLKOUT_SIG_PVT_PERI_GROUP1

    PVT peripheral group 1 clock

  enumerator CLKOUT_SIG_CRYPTO_SEC

    Security / crypto accelerator module clock

  enumerator CLKOUT_SIG_LEDC1

    LED PWM controller instance 1 module clock

  enumerator CLKOUT_SIG_IOMUX

    IO MUX clock

  enumerator CLKOUT_SIG_REF_50M

    50MHz reference clock

  enumerator CLKOUT_SIG_REF_120M

    120MHz reference clock

  enumerator CLKOUT_SIG_REF_160M

    160MHz reference clock

  enumerator CLKOUT_SIG_REF_20M

    20MHz reference clock

  enumerator CLKOUT_SIG_REF_240M

    240MHz reference clock

  enumerator CLKOUT_SIG_REF_25M

    25MHz reference clock

  enumerator CLKOUT_SIG_REF_80M

    80MHz reference clock

  enumerator CLKOUT_SIG_REF_60M

    60MHz reference clock

  enumerator CLKOUT_SIG_MPLL

    Legacy short name; same mux as CLKOUT_SIG_MPLL_500M

  enumerator CLKOUT_SIG_BBPLL

    Legacy short name; same mux as CLKOUT_SIG_BBPLL_480M

  enumerator CLKOUT_SIG_CPLL

    Legacy short name; same mux as CLKOUT_SIG_CPLL_300M

  enumerator CLKOUT_SIG_XTAL

    Legacy short name; same mux as CLKOUT_SIG_XTAL_40M

  enumerator CLKOUT_SIG_RC_FAST

    Legacy name for RC_FAST / FOSC domain; same mux as CLKOUT_SIG_FOSC_20M

  enumerator CLKOUT_SIG_RC_SLOW

    Legacy name for RC_SLOW / SOSC domain; same mux as CLKOUT_SIG_SOSC_600KD4

  enumerator CLKOUT_SIG_XTAL32K

    Legacy short name; same mux as CLKOUT_SIG_XTAL_32K

  enumerator CLKOUT_SIG_I2S0

    Legacy short name; same mux as CLKOUT_SIG_PAD_I2S0_MCLK

  enumerator CLKOUT_SIG_I2S1

    Legacy short name; same mux as CLKOUT_SIG_PAD_I2S1_MCLK

  enumerator CLKOUT_SIG_CPU

    Legacy short name; same mux as CLKOUT_SIG_TCELL_CPU

  enumerator CLKOUT_SIG_MEM

    Legacy short name; same mux as CLKOUT_SIG_TCELL_MEM

  enumerator CLKOUT_SIG_SYS

    Legacy short name; same mux as CLKOUT_SIG_TCELL_SYS

  enumerator CLKOUT_SIG_APB

    Legacy short name; same mux as CLKOUT_SIG_TCELL_APB

  enumerator CLKOUT_SIG_PLL_F80M

    Legacy name; same mux as CLKOUT_SIG_REF_80M (80MHz reference tap)

  enumerator CLKOUT_SIG_INVALID

    Invalid mux value; channel disabled or not connected

enum soc_clk_freq_calculation_src_t

  Clock frequency calculation source selection.

  Values:

  enumerator CLK_CAL_RTC_SLOW

    Select to calculate frequency of RTC_SLOW_CLK

  enumerator CLK_CAL_MPLL

    Select to calculate frequency of MPLL_CLK

  enumerator CLK_CAL_BBPLL

    Select to calculate frequency of BBPLL_CLK

  enumerator CLK_CAL_CPLL

    Select to calculate frequency of CPLL_CLK

  enumerator CLK_CAL_APLL

    Select to calculate frequency of APLL_CLK

  enumerator CLK_CAL_AHB

    Select to calculate frequency of AHB_CLK

  enumerator CLK_CAL_APB

    Select to calculate frequency of APB_CLK

  enumerator CLK_CAL_ROM

    Select to calculate frequency of ROM_CLK

  enumerator CLK_CAL_RC_FAST

    Select to calculate frequency of RC_FAST_CLK

  enumerator CLK_CAL_RC_SLOW

    Select to calculate frequency of RC_SLOW_CLK

  enumerator CLK_CAL_32K_XTAL

    Select to calculate frequency of XTAL32K_CLK

  enumerator CLK_CAL_XTAL

    Select to calculate frequency of XTAL_CLK

  enumerator CLK_CAL_UART0_PAD

    Select to calculate frequency of UART0_PAD_CLK

  enumerator CLK_CAL_CORE0

    Select to calculate frequency of CORE0_CLK

  enumerator CLK_CAL_CORE1

    Select to calculate frequency of CORE1_CLK

enum soc_periph_cordic_clk_src_t

  Values:

  enumerator CORDIC_CLK_SRC_XTAL
  enumerator CORDIC_CLK_SRC_PLL_F160M
  enumerator CORDIC_CLK_SRC_RC_FAST
  enumerator CORDIC_CLK_SRC_DEFAULT

enum soc_periph_pcnt_clk_src_t

  Type of PCNT clock source.

  Values:

  enumerator PCNT_CLK_SRC_APB

    Select APB as the source clock

  enumerator PCNT_CLK_SRC_DEFAULT

    Select APB as the default choice

enum soc_periph_adc_digi_clk_src_t

  Values:

  enumerator ADC_DIGI_CLK_SRC_RC_FAST

    Select FOSC (internal RC oscillator) as ADC source clock

  enumerator ADC_DIGI_CLK_SRC_XTAL

    Select XTAL as ADC source clock

  enumerator ADC_DIGI_CLK_SRC_DEFAULT

    Select XTAL as the default clock choice

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_periph_emac_clk_out_src_t

  Values:

  enumerator EMAC_CLK_OUT_SRC_MPLL
  enumerator EMAC_CLK_OUT_SRC_CPLL
  enumerator EMAC_CLK_OUT_SRC_APLL
  enumerator EMAC_CLK_OUT_SRC_DEFAULT

enum soc_periph_emac_ref_phy_clk_src_t

  Values:

  enumerator EMAC_REF_PHY_CLK_SRC_MPLL
  enumerator EMAC_REF_PHY_CLK_SRC_CPLL
  enumerator EMAC_REF_PHY_CLK_SRC_DEFAULT

enum soc_periph_emac_ptp_clk_src_t

  Values:

  enumerator EMAC_PTP_CLK_SRC_XTAL
  enumerator EMAC_PTP_CLK_SRC_PLL_F80M
  enumerator EMAC_PTP_CLK_SRC_DEFAULT

### 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.

  参数:

    - 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

  返回:

    - ESP_OK Success

    - ESP_ERR_INVALID_ARG Parameter error

    - ESP_FAIL Calibration failed

esp_err_t esp_clk_tree_src_set_freq_hz(soc_module_clk_t clk_src, uint32_t expt_freq_value, uint32_t *ret_freq_value)

  Set frequency of module clock source.

  参数:

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

    - expt_freq_value -- [in] Expected frequency of the clock source, in Hz

    - ret_freq_value -- [out] Real frequency of the clock source, in Hz

  返回:

    - ESP_OK Success

    - ESP_ERR_INVALID_ARG Parameter error

    - ESP_ERR_NOT_SUPPORTED Unsupported clock source

### 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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