1 /* 2 * SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD 3 * 4 * SPDX-License-Identifier: Apache-2.0 5 */ 6 7 #pragma once 8 #include <stdint.h> 9 10 #ifdef __cplusplus 11 extern "C" { 12 #endif 13 14 /** 15 * @file esp_clk.h 16 * 17 * This file contains declarations of clock related functions. 18 */ 19 20 /** 21 * @brief Get the calibration value of RTC slow clock 22 * 23 * The value is in the same format as returned by rtc_clk_cal (microseconds, 24 * in Q13.19 fixed-point format). 25 * 26 * @return the calibration value obtained using rtc_clk_cal, at startup time 27 */ 28 uint32_t esp_clk_slowclk_cal_get(void); 29 30 /** 31 * @brief Update the calibration value of RTC slow clock 32 * 33 * The value has to be in the same format as returned by rtc_clk_cal (microseconds, 34 * in Q13.19 fixed-point format). 35 * This value is used by timekeeping functions (such as gettimeofday) to 36 * calculate current time based on RTC counter value. 37 * @param value calibration value obtained using rtc_clk_cal 38 */ 39 void esp_clk_slowclk_cal_set(uint32_t value); 40 41 /** 42 * @brief Return current CPU clock frequency 43 * When frequency switching is performed, this frequency may change. 44 * However it is guaranteed that the frequency never changes with a critical 45 * section. 46 * 47 * @return CPU clock frequency, in Hz 48 */ 49 int esp_clk_cpu_freq(void); 50 51 /** 52 * @brief Return current APB clock frequency 53 * 54 * When frequency switching is performed, this frequency may change. 55 * However it is guaranteed that the frequency never changes with a critical 56 * section. 57 * 58 * @return APB clock frequency, in Hz 59 */ 60 int esp_clk_apb_freq(void); 61 62 /** 63 * @brief Return frequency of the main XTAL 64 * 65 * Frequency of the main XTAL can be either auto-detected or set at compile 66 * time (see CONFIG_XTAL_FREQ_SEL sdkconfig option). In both cases, this 67 * function returns the actual value at run time. 68 * 69 * @return XTAL frequency, in Hz 70 */ 71 int esp_clk_xtal_freq(void); 72 73 74 /** 75 * @brief Read value of RTC counter, converting it to microseconds 76 * @attention The value returned by this function may change abruptly when 77 * calibration value of RTC counter is updated via esp_clk_slowclk_cal_set 78 * function. This should not happen unless application calls esp_clk_slowclk_cal_set. 79 * In ESP-IDF, esp_clk_slowclk_cal_set is only called in startup code. 80 * 81 * @return Value or RTC counter, expressed in microseconds 82 */ 83 uint64_t esp_clk_rtc_time(void); 84 85 /** 86 * @brief obtain internal critical section used esp_clk implementation. 87 * 88 * This is used by the esp_light_sleep_start() to avoid deadlocking when it 89 * calls esp_clk related API after stalling the other CPU. 90 */ 91 void esp_clk_private_lock(void); 92 93 /** 94 * @brief counterpart of esp_clk_private_lock 95 */ 96 void esp_clk_private_unlock(void); 97 98 #ifdef __cplusplus 99 } 100 #endif 101
