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_LPTICKER_API_H
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20 | #define MBED_LPTICKER_API_H
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21 |
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22 | #include "device.h"
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23 |
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24 | #if DEVICE_LPTICKER
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25 |
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26 | #include "hal/ticker_api.h"
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27 |
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28 | #ifdef __cplusplus
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29 | extern "C" {
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30 | #endif
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31 |
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32 | /**
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33 | * \defgroup hal_lp_ticker Low Power Ticker
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34 | * Low level interface to the low power ticker of a target
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35 | *
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36 | * # Defined behavior
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37 | * * Has a reported frequency between 4KHz and 64KHz - verified by ::lp_ticker_info_test
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38 | * * Has a counter that is at least 12 bits wide - verified by ::lp_ticker_info_test
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39 | * * Continues operating in deep sleep mode - verified by ::lp_ticker_deepsleep_test
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40 | * * All behavior defined by the @ref hal_ticker_shared "ticker specification"
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41 | *
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42 | * # Undefined behavior
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43 | * * See the @ref hal_ticker_shared "ticker specification"
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44 | * * Calling any function other than lp_ticker_init after calling lp_ticker_free
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45 | *
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46 | * # Potential bugs
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47 | * * Glitches due to ripple counter - Verified by ::lp_ticker_glitch_test
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48 | *
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49 | * @see hal_lp_ticker_tests
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50 | *
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51 | * @{
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52 | */
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53 |
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54 | /**
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55 | * \defgroup hal_lp_ticker_tests Low Power Ticker tests
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56 | * Tests to validate the proper implementation of the low power ticker
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57 | *
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58 | * To run the low power ticker hal tests use the command:
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59 | *
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60 | * mbed test -t <toolchain> -m <target> -n tests-mbed_hal-common_ticker*,tests-mbed_hal-lp_ticker*
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61 | *
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62 | */
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63 |
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64 | typedef void (*ticker_irq_handler_type)(const ticker_data_t *const);
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65 |
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66 | /** Set low power ticker IRQ handler
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67 | *
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68 | * @param ticker_irq_handler IRQ handler to be connected
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69 | *
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70 | * @return previous ticker IRQ handler
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71 | *
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72 | * @note by default IRQ handler is set to ::ticker_irq_handler
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73 | * @note this function is primarily for testing purposes and it's not required part of HAL implementation
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74 | *
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75 | */
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76 | ticker_irq_handler_type set_lp_ticker_irq_handler(ticker_irq_handler_type ticker_irq_handler);
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77 |
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78 | /** Get low power ticker's data
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79 | *
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80 | * @return The low power ticker data
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81 | */
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82 | const ticker_data_t *get_lp_ticker_data(void);
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83 |
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84 | /** The wrapper for ticker_irq_handler, to pass lp ticker's data
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85 | *
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86 | */
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87 | void lp_ticker_irq_handler(void);
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88 |
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89 | /* HAL lp ticker */
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90 |
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91 | /** Initialize the low power ticker
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92 | *
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93 | * Initialize or re-initialize the ticker. This resets all the
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94 | * clocking and prescaler registers, along with disabling
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95 | * the compare interrupt.
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96 | *
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97 | * Pseudo Code:
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98 | * @code
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99 | * void lp_ticker_init()
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100 | * {
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101 | * // Enable clock gate so processor can read LPTMR registers
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102 | * POWER_CTRL |= POWER_CTRL_LPTMR_Msk;
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103 | *
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104 | * // Disable the timer and ensure it is powered down
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105 | * LPTMR_CTRL &= ~(LPTMR_CTRL_ENABLE_Msk | LPTMR_CTRL_COMPARE_ENABLE_Msk);
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106 | *
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107 | * // Configure divisors - no division necessary
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108 | * LPTMR_PRESCALE = 0;
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109 | * LPTMR_CTRL |= LPTMR_CTRL_ENABLE_Msk;
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110 | *
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111 | * // Install the interrupt handler
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112 | * NVIC_SetVector(LPTMR_IRQn, (uint32_t)lp_ticker_irq_handler);
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113 | * NVIC_EnableIRQ(LPTMR_IRQn);
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114 | * }
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115 | * @endcode
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116 | */
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117 | void lp_ticker_init(void);
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118 |
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119 | /** Deinitialize the lower power ticker
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120 | *
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121 | * Powerdown the lp ticker in preparation for sleep, powerdown, or reset.
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122 | *
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123 | * After calling this function no other ticker functions should be called except
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124 | * lp_ticker_init(). Calling any function other than init after freeing is
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125 | * undefined.
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126 | *
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127 | * @note This function stops the ticker from counting.
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128 | */
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129 | void lp_ticker_free(void);
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130 |
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131 | /** Read the current tick
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132 | *
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133 | * If no rollover has occurred, the seconds passed since lp_ticker_init()
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134 | * was called can be found by dividing the ticks returned by this function
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135 | * by the frequency returned by ::lp_ticker_get_info.
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136 | *
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137 | * @return The current timer's counter value in ticks
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138 | *
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139 | * Pseudo Code:
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140 | * @code
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141 | * uint32_t lp_ticker_read()
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142 | * {
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143 | * uint16_t count;
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144 | * uint16_t last_count;
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145 | *
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146 | * // Loop until the same tick is read twice since this
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147 | * // is ripple counter on a different clock domain.
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148 | * count = LPTMR_COUNT;
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149 | * do {
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150 | * last_count = count;
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151 | * count = LPTMR_COUNT;
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152 | * } while (last_count != count);
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153 | *
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154 | * return count;
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155 | * }
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156 | * @endcode
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157 | */
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158 | uint32_t lp_ticker_read(void);
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159 |
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160 | /** Set interrupt for specified timestamp
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161 | *
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162 | * @param timestamp The time in ticks to be set
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163 | *
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164 | * @note no special handling needs to be done for times in the past
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165 | * as the common timer code will detect this and call
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166 | * lp_ticker_fire_interrupt() if this is the case
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167 | *
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168 | * @note calling this function with timestamp of more than the supported
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169 | * number of bits returned by ::lp_ticker_get_info results in undefined
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170 | * behavior.
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171 | *
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172 | * Pseudo Code:
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173 | * @code
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174 | * void lp_ticker_set_interrupt(timestamp_t timestamp)
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175 | * {
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176 | * LPTMR_COMPARE = timestamp;
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177 | * LPTMR_CTRL |= LPTMR_CTRL_COMPARE_ENABLE_Msk;
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178 | * }
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179 | * @endcode
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180 | */
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181 | void lp_ticker_set_interrupt(timestamp_t timestamp);
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182 |
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183 | /** Disable low power ticker interrupt
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184 | *
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185 | * Pseudo Code:
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186 | * @code
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187 | * void lp_ticker_disable_interrupt(void)
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188 | * {
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189 | * // Disable the compare interrupt
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190 | * LPTMR_CTRL &= ~LPTMR_CTRL_COMPARE_ENABLE_Msk;
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191 | * }
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192 | * @endcode
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193 | */
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194 | void lp_ticker_disable_interrupt(void);
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195 |
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196 | /** Clear the low power ticker interrupt
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197 | *
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198 | * Pseudo Code:
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199 | * @code
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200 | * void lp_ticker_clear_interrupt(void)
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201 | * {
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202 | * // Write to the ICR (interrupt clear register) of the LPTMR
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203 | * LPTMR_ICR = LPTMR_ICR_COMPARE_Msk;
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204 | * }
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205 | * @endcode
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206 | */
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207 | void lp_ticker_clear_interrupt(void);
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208 |
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209 | /** Set pending interrupt that should be fired right away.
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210 | *
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211 | * Pseudo Code:
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212 | * @code
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213 | * void lp_ticker_fire_interrupt(void)
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214 | * {
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215 | * NVIC_SetPendingIRQ(LPTMR_IRQn);
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216 | * }
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217 | * @endcode
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218 | */
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219 | void lp_ticker_fire_interrupt(void);
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220 |
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221 | /** Get frequency and counter bits of this ticker.
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222 | *
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223 | * Pseudo Code:
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224 | * @code
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225 | * const ticker_info_t* lp_ticker_get_info()
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226 | * {
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227 | * static const ticker_info_t info = {
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228 | * 32768, // 32KHz
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229 | * 16 // 16 bit counter
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230 | * };
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231 | * return &info;
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232 | * }
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233 | * @endcode
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234 | */
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235 | const ticker_info_t *lp_ticker_get_info(void);
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236 |
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237 | /**@}*/
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238 |
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239 | #ifdef __cplusplus
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240 | }
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241 | #endif
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242 |
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243 | #endif
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244 |
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245 | #endif
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246 |
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247 | /** @}*/
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