/*
* SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#pragma once
/**
* @file esp_timer.h
* @brief microsecond-precision 64-bit timer API, replacement for ets_timer
*
* esp_timer APIs allow components to receive callbacks when a hardware timer
* reaches certain value. The timer provides microsecond accuracy and
* up to 64 bit range. Note that while the timer itself provides microsecond
* accuracy, callbacks are dispatched from an auxiliary task. Some time is
* needed to notify this task from timer ISR, and then to invoke the callback.
* If more than one callback needs to be dispatched at any particular time,
* each subsequent callback will be dispatched only when the previous callback
* returns. Therefore, callbacks should not do much work; instead, they should
* use RTOS notification mechanisms (queues, semaphores, event groups, etc.) to
* pass information to other tasks.
*
* To be implemented: it should be possible to request the callback to be called
* directly from the ISR. This reduces the latency, but has potential impact on
* all other callbacks which need to be dispatched. This option should only be
* used for simple callback functions, which do not take longer than a few
* microseconds to run.
*
* Implementation note: on the ESP32, esp_timer APIs use the "legacy" FRC2
* timer. Timer callbacks are called from a task running on the PRO CPU.
*/
#include <stdint.h>
#include <stdio.h>
#include <stdbool.h>
#include "esp_err.h"
#include "sdkconfig.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Opaque type representing a single esp_timer
*/
typedef struct esp_timer* esp_timer_handle_t;
/**
* @brief Timer callback function type
* @param arg pointer to opaque user-specific data
*/
typedef void (*esp_timer_cb_t)(void* arg);
/**
* @brief Method for dispatching timer callback
*/
typedef enum {
ESP_TIMER_TASK, //!< Callback is called from timer task
#ifdef CONFIG_ESP_TIMER_SUPPORTS_ISR_DISPATCH_METHOD
ESP_TIMER_ISR, //!< Callback is called from timer ISR
#endif
ESP_TIMER_MAX, //!< Count of the methods for dispatching timer callback
} esp_timer_dispatch_t;
/**
* @brief Timer configuration passed to esp_timer_create
*/
typedef struct {
esp_timer_cb_t callback; //!< Function to call when timer expires
void* arg; //!< Argument to pass to the callback
esp_timer_dispatch_t dispatch_method; //!< Call the callback from task or from ISR
const char* name; //!< Timer name, used in esp_timer_dump function
bool skip_unhandled_events; //!< Skip unhandled events for periodic timers
} esp_timer_create_args_t;
/**
* @brief Minimal initialization of esp_timer
*
* @note This function is called from startup code. Applications do not need
* to call this function before using other esp_timer APIs.
*
* This function can be called very early in startup process, after this call
* only esp_timer_get_time function can be used.
*
* @return
* - ESP_OK on success
*/
esp_err_t esp_timer_early_init(void);
/**
* @brief Initialize esp_timer library
*
* @note This function is called from startup code. Applications do not need
* to call this function before using other esp_timer APIs.
* Before calling this function, esp_timer_early_init must be called by the
* startup code.
*
* @return
* - ESP_OK on success
* - ESP_ERR_NO_MEM if allocation has failed
* - ESP_ERR_INVALID_STATE if already initialized
* - other errors from interrupt allocator
*/
esp_err_t esp_timer_init(void);
/**
* @brief De-initialize esp_timer library
*
* @note Normally this function should not be called from applications
*
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_STATE if not yet initialized
*/
esp_err_t esp_timer_deinit(void);
/**
* @brief Create an esp_timer instance
*
* @note When done using the timer, delete it with esp_timer_delete function.
*
* @param create_args Pointer to a structure with timer creation arguments.
* Not saved by the library, can be allocated on the stack.
* @param[out] out_handle Output, pointer to esp_timer_handle_t variable which
* will hold the created timer handle.
*
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_ARG if some of the create_args are not valid
* - ESP_ERR_INVALID_STATE if esp_timer library is not initialized yet
* - ESP_ERR_NO_MEM if memory allocation fails
*/
esp_err_t esp_timer_create(const esp_timer_create_args_t* create_args,
esp_timer_handle_t* out_handle);
/**
* @brief Start one-shot timer
*
* Timer should not be running when this function is called.
*
* @param timer timer handle created using esp_timer_create
* @param timeout_us timer timeout, in microseconds relative to the current moment
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_ARG if the handle is invalid
* - ESP_ERR_INVALID_STATE if the timer is already running
*/
esp_err_t esp_timer_start_once(esp_timer_handle_t timer, uint64_t timeout_us);
/**
* @brief Start a periodic timer
*
* Timer should not be running when this function is called. This function will
* start the timer which will trigger every 'period' microseconds.
*
* @param timer timer handle created using esp_timer_create
* @param period timer period, in microseconds
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_ARG if the handle is invalid
* - ESP_ERR_INVALID_STATE if the timer is already running
*/
esp_err_t esp_timer_start_periodic(esp_timer_handle_t timer, uint64_t period);
/**
* @brief Stop the timer
*
* This function stops the timer previously started using esp_timer_start_once
* or esp_timer_start_periodic.
*
* @param timer timer handle created using esp_timer_create
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_STATE if the timer is not running
*/
esp_err_t esp_timer_stop(esp_timer_handle_t timer);
/**
* @brief Delete an esp_timer instance
*
* The timer must be stopped before deleting. A one-shot timer which has expired
* does not need to be stopped.
*
* @param timer timer handle allocated using esp_timer_create
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_STATE if the timer is running
*/
esp_err_t esp_timer_delete(esp_timer_handle_t timer);
/**
* @brief Get time in microseconds since boot
* @return number of microseconds since underlying timer has been started
*/
int64_t esp_timer_get_time(void);
/**
* @brief Get the timestamp when the next timeout is expected to occur
* @return Timestamp of the nearest timer event, in microseconds.
* The timebase is the same as for the values returned by esp_timer_get_time.
*/
int64_t esp_timer_get_next_alarm(void);
/**
* @brief Get the timestamp when the next timeout is expected to occur skipping those which have skip_unhandled_events flag
* @return Timestamp of the nearest timer event, in microseconds.
* The timebase is the same as for the values returned by esp_timer_get_time.
*/
int64_t esp_timer_get_next_alarm_for_wake_up(void);
/**
* @brief Get the period of a timer
*
* This function fetches the timeout period of a timer.
*
* @note The timeout period is the time interval with which a timer restarts after expiry. For one-shot timers, the
* period is 0 as there is no periodicity associated with such timers.
*
* @param timer timer handle allocated using esp_timer_create
* @param period memory to store the timer period value in microseconds
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_ARG if the arguments are invalid
*/
esp_err_t esp_timer_get_period(esp_timer_handle_t timer, uint64_t *period);
/**
* @brief Get the expiry time of a one-shot timer
*
* This function fetches the expiry time of a one-shot timer.
*
* @note This API returns a valid expiry time only for a one-shot timer. It returns an error if the timer handle passed
* to the function is for a periodic timer.
*
* @param timer timer handle allocated using esp_timer_create
* @param expiry memory to store the timeout value in microseconds
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_ARG if the arguments are invalid
* - ESP_ERR_NOT_SUPPORTED if the timer type is periodic
*/
esp_err_t esp_timer_get_expiry_time(esp_timer_handle_t timer, uint64_t *expiry);
/**
* @brief Dump the list of timers to a stream
*
* If CONFIG_ESP_TIMER_PROFILING option is enabled, this prints the list of all
* the existing timers. Otherwise, only the list active timers is printed.
*
* The format is:
*
* name period alarm times_armed times_triggered total_callback_run_time
*
* where:
*
* name — timer name (if CONFIG_ESP_TIMER_PROFILING is defined), or timer pointer
* period — period of timer, in microseconds, or 0 for one-shot timer
* alarm - time of the next alarm, in microseconds since boot, or 0 if the timer
* is not started
*
* The following fields are printed if CONFIG_ESP_TIMER_PROFILING is defined:
*
* times_armed — number of times the timer was armed via esp_timer_start_X
* times_triggered - number of times the callback was called
* total_callback_run_time - total time taken by callback to execute, across all calls
*
* @param stream stream (such as stdout) to dump the information to
* @return
* - ESP_OK on success
* - ESP_ERR_NO_MEM if can not allocate temporary buffer for the output
*/
esp_err_t esp_timer_dump(FILE* stream);
#ifdef CONFIG_ESP_TIMER_SUPPORTS_ISR_DISPATCH_METHOD
/**
* @brief Requests a context switch from a timer callback function.
*
* This only works for a timer that has an ISR dispatch method.
* The context switch will be called after all ISR dispatch timers have been processed.
*/
void esp_timer_isr_dispatch_need_yield(void);
#endif // CONFIG_ESP_TIMER_SUPPORTS_ISR_DISPATCH_METHOD
/**
* @brief Returns status of a timer, active or not
*
* This function is used to identify if the timer is still active or not.
*
* @param timer timer handle created using esp_timer_create
* @return
* - 1 if timer is still active
* - 0 if timer is not active.
*/
bool esp_timer_is_active(esp_timer_handle_t timer);
#ifdef __cplusplus
}
#endif