Mbed OS Reference | ticker_api.h Source File

 
 /** \addtogroup hal */
 /** @{*/
 /* mbed Microcontroller Library
  * Copyright (c) 2015 ARM Limited
  * SPDX-License-Identifier: Apache-2.0
  *
  * 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.
  */
 #ifndef MBED_TICKER_API_H
 #define MBED_TICKER_API_H
 
 #include <stdint.h>
 #include <stdbool.h>
 #include "device.h"
 
 /**
  * Legacy format representing a timestamp in us.
  * Given it is modeled as a 32 bit integer, this type can represent timestamp
  * up to 4294 seconds (71 minutes).
  * Prefer using us_timestamp_t which store timestamp as 64 bits integer.
  */
 typedef uint32_t timestamp_t;
 
 /**
  * A us timestamp stored in a 64 bit integer.
  * Can store timestamp up to 584810 years.
  */
 typedef uint64_t us_timestamp_t;
 
 /** Ticker's event structure
  */
 typedef struct ticker_event_s {
     us_timestamp_t         timestamp; /**< Event's timestamp */
     uint32_t               id;        /**< TimerEvent object */
     struct ticker_event_s *next;      /**< Next event in the queue */
 } ticker_event_t;
 
 typedef void (*ticker_event_handler)(uint32_t id);
 
 /** Information about the ticker implementation
  */
 typedef struct {
     uint32_t frequency;                           /**< Frequency in Hz this ticker runs at */
     uint32_t bits;                                /**< Number of bits this ticker supports */
 } ticker_info_t;
 
 
 /** Ticker's interface structure - required API for a ticker
  */
 typedef struct {
     void (*init)(void);                           /**< Init function */
     uint32_t (*read)(void);                       /**< Read function */
     void (*disable_interrupt)(void);              /**< Disable interrupt function */
     void (*clear_interrupt)(void);                /**< Clear interrupt function */
     void (*set_interrupt)(timestamp_t timestamp); /**< Set interrupt function */
     void (*fire_interrupt)(void);                 /**< Fire interrupt right-away */
     void (*free)(void);                           /**< Disable function */
     const ticker_info_t *(*get_info)(void);       /**< Return info about this ticker's implementation */
     bool runs_in_deep_sleep;                      /**< Whether ticker operates in deep sleep */
 } ticker_interface_t;
 
 /** Ticker's event queue structure
  */
 typedef struct {
     ticker_event_handler event_handler; /**< Event handler */
     ticker_event_t *head;               /**< A pointer to head */
     uint32_t frequency;                 /**< Frequency of the timer in Hz */
     uint32_t bitmask;                   /**< Mask to be applied to time values read */
     uint32_t max_delta;                 /**< Largest delta in ticks that can be used when scheduling */
     uint64_t max_delta_us;              /**< Largest delta in us that can be used when scheduling */
     uint32_t tick_last_read;            /**< Last tick read */
     uint64_t tick_remainder;            /**< Ticks that have not been added to base_time */
     us_timestamp_t present_time;        /**< Store the timestamp used for present time */
     bool initialized;                   /**< Indicate if the instance is initialized */
     bool dispatching;                   /**< The function ticker_irq_handler is dispatching */
     bool suspended;                     /**< Indicate if the instance is suspended */
     uint8_t frequency_shifts;           /**< If frequency is a value of 2^n, this is n, otherwise 0 */
 } ticker_event_queue_t;
 
 /** Ticker's data structure
  */
 typedef struct {
     const ticker_interface_t *interface; /**< Ticker's interface */
     ticker_event_queue_t *queue;         /**< Ticker's event queue */
 } ticker_data_t;
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /**
  * \defgroup hal_ticker Ticker HAL functions
  * @{
  */
 
 /** Initialize a ticker and set the event handler
  *
  * @param ticker The ticker object.
  * @param handler A handler to be set
  */
 void ticker_set_handler(const ticker_data_t *const ticker, ticker_event_handler handler);
 
 /** IRQ handler that goes through the events to trigger overdue events.
  *
  * @param ticker The ticker object.
  */
 void ticker_irq_handler(const ticker_data_t *const ticker);
 
 /** Remove an event from the queue
  *
  * @param ticker The ticker object.
  * @param obj  The event object to be removed from the queue
  */
 void ticker_remove_event(const ticker_data_t *const ticker, ticker_event_t *obj);
 
 /** Insert an event to the queue
  *
  * The event will be executed in timestamp - ticker_read().
  *
  * @warning This function does not consider timestamp in the past. If an event
  * is inserted with a timestamp less than the current timestamp then the event
  * will be executed in timestamp - ticker_read() us.
  * The internal counter wrap very quickly it is hard to decide weither an
  * event is in the past or in 1 hour.
  *
  * @note prefer the use of ticker_insert_event_us which allows registration of
  * absolute timestamp.
  *
  * @param ticker    The ticker object.
  * @param obj       The event object to be inserted to the queue
  * @param timestamp The event's timestamp
  * @param id        The event object
  */
 void ticker_insert_event(const ticker_data_t *const ticker, ticker_event_t *obj, timestamp_t timestamp, uint32_t id);
 
 /** Insert an event to the queue
  *
  * The event will be executed in timestamp - ticker_read_us() us.
  *
  * @note If an event is inserted with a timestamp less than the current
  * timestamp then the event will be scheduled immediately resulting in
  * an instant call to event handler.
  *
  * @param ticker    The ticker object.
  * @param obj       The event object to be inserted to the queue
  * @param timestamp The event's timestamp
  * @param id        The event object
  */
 void ticker_insert_event_us(const ticker_data_t *const ticker, ticker_event_t *obj, us_timestamp_t timestamp, uint32_t id);
 
 /** Read the current (relative) ticker's timestamp
  *
  * @warning Return a relative timestamp because the counter wrap every 4294
  * seconds.
  *
  * @param ticker The ticker object.
  * @return The current timestamp
  */
 timestamp_t ticker_read(const ticker_data_t *const ticker);
 
 /** Read the current (absolute) ticker's timestamp
  *
  * @warning Return an absolute timestamp counting from the initialization of the
  * ticker.
  *
  * @param ticker The ticker object.
  * @return The current timestamp
  */
 us_timestamp_t ticker_read_us(const ticker_data_t *const ticker);
 
 /** Read the next event's timestamp
  *
  * @param ticker        The ticker object.
  * @param timestamp     The timestamp object.
  * @return 1 if timestamp is pending event, 0 if there's no event pending
  */
 int ticker_get_next_timestamp(const ticker_data_t *const ticker, timestamp_t *timestamp);
 
 /** Suspend this ticker
  *
  * When suspended reads will always return the same time and no
  * events will be dispatched. When suspended the common layer
  * will only ever call the interface function clear_interrupt()
  * and that is only if ticker_irq_handler is called.
  *
  *
  * @param ticker        The ticker object.
  */
 void ticker_suspend(const ticker_data_t *const ticker);
 
 /** Resume this ticker
  *
  * When resumed the ticker will ignore any time that has passed
  * and continue counting up where it left off.
  *
  * @param ticker        The ticker object.
  */
 void ticker_resume(const ticker_data_t *const ticker);
 
 /* Private functions
  *
  * @cond PRIVATE
  *
  */
 
 int _ticker_match_interval_passed(timestamp_t prev_tick, timestamp_t cur_tick, timestamp_t match_tick);
 
 /*
  * @endcond PRIVATE
  *
  */
 
 /**@}*/
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif
 
 /** @}*/
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