1 |
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2 | /** \addtogroup hal */
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3 | /** @{*/
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4 | /* mbed Microcontroller Library
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5 | * Copyright (c) 2015 ARM Limited
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6 | *
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7 | * Licensed under the Apache License, Version 2.0 (the "License");
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8 | * you may not use this file except in compliance with the License.
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9 | * You may obtain a copy of the License at
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10 | *
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11 | * http://www.apache.org/licenses/LICENSE-2.0
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12 | *
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13 | * Unless required by applicable law or agreed to in writing, software
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14 | * distributed under the License is distributed on an "AS IS" BASIS,
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15 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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16 | * See the License for the specific language governing permissions and
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17 | * limitations under the License.
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18 | */
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19 | #ifndef MBED_TICKER_API_H
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20 | #define MBED_TICKER_API_H
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21 |
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22 | #include <stdint.h>
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23 | #include <stdbool.h>
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24 | #include "device.h"
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25 |
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26 | /**
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27 | * Legacy format representing a timestamp in us.
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28 | * Given it is modeled as a 32 bit integer, this type can represent timestamp
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29 | * up to 4294 seconds (71 minutes).
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30 | * Prefer using us_timestamp_t which store timestamp as 64 bits integer.
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31 | */
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32 | typedef uint32_t timestamp_t;
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33 |
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34 | /**
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35 | * A us timestamp stored in a 64 bit integer.
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36 | * Can store timestamp up to 584810 years.
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37 | */
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38 | typedef uint64_t us_timestamp_t;
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39 |
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40 | /** Ticker's event structure
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41 | */
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42 | typedef struct ticker_event_s {
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43 | us_timestamp_t timestamp; /**< Event's timestamp */
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44 | uint32_t id; /**< TimerEvent object */
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45 | struct ticker_event_s *next; /**< Next event in the queue */
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46 | } ticker_event_t;
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47 |
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48 | typedef void (*ticker_event_handler)(uint32_t id);
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49 |
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50 | /** Information about the ticker implementation
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51 | */
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52 | typedef struct {
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53 | uint32_t frequency; /**< Frequency in Hz this ticker runs at */
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54 | uint32_t bits; /**< Number of bits this ticker supports */
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55 | } ticker_info_t;
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56 |
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57 |
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58 | /** Ticker's interface structure - required API for a ticker
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59 | */
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60 | typedef struct {
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61 | void (*init)(void); /**< Init function */
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62 | uint32_t (*read)(void); /**< Read function */
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63 | void (*disable_interrupt)(void); /**< Disable interrupt function */
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64 | void (*clear_interrupt)(void); /**< Clear interrupt function */
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65 | void (*set_interrupt)(timestamp_t timestamp); /**< Set interrupt function */
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66 | void (*fire_interrupt)(void); /**< Fire interrupt right-away */
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67 | void (*free)(void); /**< Disable function */
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68 | const ticker_info_t *(*get_info)(void); /**< Return info about this ticker's implementation */
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69 | } ticker_interface_t;
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70 |
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71 | /** Ticker's event queue structure
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72 | */
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73 | typedef struct {
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74 | ticker_event_handler event_handler; /**< Event handler */
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75 | ticker_event_t *head; /**< A pointer to head */
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76 | uint32_t frequency; /**< Frequency of the timer in Hz */
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77 | uint32_t bitmask; /**< Mask to be applied to time values read */
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78 | uint32_t max_delta; /**< Largest delta in ticks that can be used when scheduling */
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79 | uint64_t max_delta_us; /**< Largest delta in us that can be used when scheduling */
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80 | uint32_t tick_last_read; /**< Last tick read */
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81 | uint64_t tick_remainder; /**< Ticks that have not been added to base_time */
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82 | us_timestamp_t present_time; /**< Store the timestamp used for present time */
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83 | bool initialized; /**< Indicate if the instance is initialized */
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84 | bool dispatching; /**< The function ticker_irq_handler is dispatching */
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85 | bool suspended; /**< Indicate if the instance is suspended */
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86 | uint8_t frequency_shifts; /**< If frequency is a value of 2^n, this is n, otherwise 0 */
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87 | } ticker_event_queue_t;
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88 |
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89 | /** Ticker's data structure
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90 | */
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91 | typedef struct {
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92 | const ticker_interface_t *interface; /**< Ticker's interface */
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93 | ticker_event_queue_t *queue; /**< Ticker's event queue */
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94 | } ticker_data_t;
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95 |
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96 | #ifdef __cplusplus
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97 | extern "C" {
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98 | #endif
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99 |
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100 | /**
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101 | * \defgroup hal_ticker Ticker HAL functions
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102 | * @{
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103 | */
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104 |
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105 | /** Initialize a ticker and set the event handler
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106 | *
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107 | * @param ticker The ticker object.
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108 | * @param handler A handler to be set
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109 | */
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110 | void ticker_set_handler(const ticker_data_t *const ticker, ticker_event_handler handler);
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111 |
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112 | /** IRQ handler that goes through the events to trigger overdue events.
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113 | *
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114 | * @param ticker The ticker object.
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115 | */
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116 | void ticker_irq_handler(const ticker_data_t *const ticker);
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117 |
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118 | /** Remove an event from the queue
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119 | *
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120 | * @param ticker The ticker object.
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121 | * @param obj The event object to be removed from the queue
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122 | */
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123 | void ticker_remove_event(const ticker_data_t *const ticker, ticker_event_t *obj);
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124 |
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125 | /** Insert an event to the queue
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126 | *
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127 | * The event will be executed in timestamp - ticker_read().
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128 | *
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129 | * @warning This function does not consider timestamp in the past. If an event
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130 | * is inserted with a timestamp less than the current timestamp then the event
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131 | * will be executed in timestamp - ticker_read() us.
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132 | * The internal counter wrap very quickly it is hard to decide weither an
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133 | * event is in the past or in 1 hour.
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134 | *
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135 | * @note prefer the use of ticker_insert_event_us which allows registration of
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136 | * absolute timestamp.
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137 | *
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138 | * @param ticker The ticker object.
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139 | * @param obj The event object to be inserted to the queue
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140 | * @param timestamp The event's timestamp
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141 | * @param id The event object
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142 | */
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143 | void ticker_insert_event(const ticker_data_t *const ticker, ticker_event_t *obj, timestamp_t timestamp, uint32_t id);
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144 |
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145 | /** Insert an event to the queue
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146 | *
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147 | * The event will be executed in timestamp - ticker_read_us() us.
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148 | *
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149 | * @note If an event is inserted with a timestamp less than the current
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150 | * timestamp then the event will be scheduled immediately resulting in
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151 | * an instant call to event handler.
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152 | *
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153 | * @param ticker The ticker object.
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154 | * @param obj The event object to be inserted to the queue
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155 | * @param timestamp The event's timestamp
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156 | * @param id The event object
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157 | */
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158 | void ticker_insert_event_us(const ticker_data_t *const ticker, ticker_event_t *obj, us_timestamp_t timestamp, uint32_t id);
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159 |
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160 | /** Read the current (relative) ticker's timestamp
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161 | *
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162 | * @warning Return a relative timestamp because the counter wrap every 4294
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163 | * seconds.
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164 | *
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165 | * @param ticker The ticker object.
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166 | * @return The current timestamp
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167 | */
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168 | timestamp_t ticker_read(const ticker_data_t *const ticker);
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169 |
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170 | /** Read the current (absolute) ticker's timestamp
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171 | *
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172 | * @warning Return an absolute timestamp counting from the initialization of the
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173 | * ticker.
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174 | *
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175 | * @param ticker The ticker object.
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176 | * @return The current timestamp
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177 | */
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178 | us_timestamp_t ticker_read_us(const ticker_data_t *const ticker);
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179 |
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180 | /** Read the next event's timestamp
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181 | *
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182 | * @param ticker The ticker object.
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183 | * @param timestamp The timestamp object.
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184 | * @return 1 if timestamp is pending event, 0 if there's no event pending
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185 | */
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186 | int ticker_get_next_timestamp(const ticker_data_t *const ticker, timestamp_t *timestamp);
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187 |
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188 | /** Suspend this ticker
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189 | *
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190 | * When suspended reads will always return the same time and no
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191 | * events will be dispatched. When suspended the common layer
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192 | * will only ever call the interface function clear_interrupt()
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193 | * and that is only if ticker_irq_handler is called.
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194 | *
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195 | *
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196 | * @param ticker The ticker object.
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197 | */
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198 | void ticker_suspend(const ticker_data_t *const ticker);
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199 |
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200 | /** Resume this ticker
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201 | *
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202 | * When resumed the ticker will ignore any time that has passed
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203 | * and continue counting up where it left off.
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204 | *
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205 | * @param ticker The ticker object.
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206 | */
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207 | void ticker_resume(const ticker_data_t *const ticker);
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208 |
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209 | /* Private functions
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210 | *
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211 | * @cond PRIVATE
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212 | *
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213 | */
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214 |
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215 | int _ticker_match_interval_passed(timestamp_t prev_tick, timestamp_t cur_tick, timestamp_t match_tick);
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216 |
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217 | /*
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218 | * @endcond PRIVATE
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219 | *
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220 | */
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221 |
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222 | /**@}*/
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223 |
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224 | #ifdef __cplusplus
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225 | }
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226 | #endif
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227 |
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228 | #endif
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229 |
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230 | /** @}*/
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