esp-idf/components/esp32/include/esp_clk.h
XiaXiaotian 4776f73ca4 Disable some peripheral clocks when cpu starts
All peripheral clocks are default enabled after chip is powered on.
    When CPU starts, if reset reason is CPU reset, disable those clocks
    that are not enabled before reset. Otherwise, disable all those
    useless clocks.
    These peripheral clocks must be enabled when the peripherals are
    initialized and disabled when they are deinitialized.
2017-08-29 11:18:42 +08:00

65 lines
2.0 KiB
C

// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#pragma once
/**
* @file esp_clk.h
*
* This file contains declarations of clock related functions.
* These functions are used in ESP-IDF components, but should not be considered
* to be part of public API.
*/
/**
* @brief Initialize clock-related settings
*
* Called from cpu_start.c, not intended to be called from other places.
* This function configures the CPU clock, RTC slow and fast clocks, and
* performs RTC slow clock calibration.
*/
void esp_clk_init(void);
/**
* @brief Get the calibration value of RTC slow clock
*
* The value is in the same format as returned by rtc_clk_cal (microseconds,
* in Q13.19 fixed-point format).
*
* @return the calibration value obtained using rtc_clk_cal, at startup time
*/
uint32_t esp_clk_slowclk_cal_get();
/**
* @brief Update the calibration value of RTC slow clock
*
* The value has to be in the same format as returned by rtc_clk_cal (microseconds,
* in Q13.19 fixed-point format).
* This value is used by timekeeping functions (such as gettimeofday) to
* calculate current time based on RTC counter value.
* @param value calibration value obtained using rtc_clk_cal
*/
void esp_clk_slowclk_cal_set(uint32_t value);
/**
* @brief Disables clock of some peripherals
*
* Called from cpu_start.c, not intended to be called from other places.
* This function disables clock of useless peripherals when cpu starts.
*/
void esp_perip_clk_init(void);