esp-idf/components/esp32/esp_timer_impl.h

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// Copyright 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_timer_impl.h
*
* @brief Interface between common and platform-specific parts of esp_timer.
*
* The functions in this header file are implemented for each supported SoC.
* High level functions defined in esp_timer.c call the functions here to
* interact with the hardware.
*/
#include <stdint.h>
#include "esp_err.h"
#include "esp_intr_alloc.h"
/**
* @brief Initialize platform specific layer of esp_timer
* @param alarm_handler function to call on timer interrupt
* @return ESP_OK, ESP_ERR_NO_MEM, or one of the errors from interrupt allocator
*/
esp_err_t esp_timer_impl_init(intr_handler_t alarm_handler);
/**
* @brief Deinitialize platform specific layer of esp_timer
*/
void esp_timer_impl_deinit();
/**
* @brief Set up the timer interrupt to fire at a particular time
*
* If the alarm time is too close in the future, implementation should set the
* alarm to the earliest time possible.
*
* @param timestamp time in microseconds when interrupt should fire (relative to
* boot time, i.e. as returned by esp_timer_impl_get_time)
*/
void esp_timer_impl_set_alarm(uint64_t timestamp);
/**
* @brief Notify esp_timer implementation that APB frequency has changed
*
* Called by the frequency switching code.
*
* @param apb_ticks_per_us new number of APB clock ticks per microsecond
*/
void esp_timer_impl_update_apb_freq(uint32_t apb_ticks_per_us);
/**
* @brief Adjust current esp_timer time by a certain value
*
* Called from light sleep code to synchronize esp_timer time with RTC time.
*
* @param time_us adjustment to apply to esp_timer time, in microseconds
*/
void esp_timer_impl_advance(int64_t time_us);
/**
* @brief Get time, in microseconds, since esp_timer_impl_init was called
* @return timestamp in microseconds
*/
uint64_t esp_timer_impl_get_time();
/**
* @brief Get minimal timer period, in microseconds
* Periods shorter than the one returned may not be possible to achieve due to
* interrupt latency and context switch time. Short period of periodic timer may
* cause the system to spend all the time servicing the interrupt and timer
* callback, preventing other tasks from running.
* @return minimal period of periodic timer, in microseconds
*/
uint64_t esp_timer_impl_get_min_period_us();
/**
* @brief obtain internal critical section used esp_timer implementation
* This can be used when a sequence of calls to esp_timer has to be made,
* and it is necessary that the state of the timer is consistent between
* the calls. Should be treated in the same way as a spinlock.
* Call esp_timer_impl_unlock to release the lock
*/
void esp_timer_impl_lock();
/**
* @brief counterpart of esp_timer_impl_lock
*/
void esp_timer_impl_unlock();