[352] | 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) 2006-2015 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_US_TICKER_API_H
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| 20 | #define MBED_US_TICKER_API_H
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| 21 |
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| 22 | #include <stdint.h>
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| 23 | #include "hal/ticker_api.h"
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| 24 |
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| 25 | #ifdef __cplusplus
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| 26 | extern "C" {
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| 27 | #endif
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| 28 |
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| 29 | /**
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[374] | 30 | * \defgroup hal_us_ticker Microsecond Ticker
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| 31 | * Low level interface to the microsecond ticker of a target
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| 32 | *
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| 33 | * # Defined behavior
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| 34 | * * Has a reported frequency between 250KHz and 8MHz - Verified by test ::us_ticker_info_test
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| 35 | * * Has a counter that is at least 16 bits wide - Verified by test ::us_ticker_info_test
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| 36 | * * All behavior defined by the @ref hal_ticker_shared "ticker specification"
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| 37 | *
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| 38 | * # Undefined behavior
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| 39 | * * See the @ref hal_ticker_shared "ticker specification"
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| 40 | *
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| 41 | * @see hal_us_ticker_tests
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| 42 | *
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[352] | 43 | * @{
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| 44 | */
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| 45 |
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[374] | 46 | /**
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| 47 | * \defgroup hal_us_ticker_tests Microsecond Ticker tests
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| 48 | * Tests to validate the proper implementation of the microsecond ticker
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| 49 | *
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| 50 | * To run the microsecond ticker hal tests use the command:
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| 51 | *
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| 52 | * mbed test -t <toolchain> -m <target> -n tests-mbed_hal-common_ticker*,tests-mbed_hal-us_ticker*
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| 53 | *
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| 54 | * @see hal_ticker_tests
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| 55 | *
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| 56 | */
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| 57 |
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| 58 | /**
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| 59 | * \defgroup hal_ticker_shared Ticker Hal
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| 60 | * Low level interface to the ticker of a target
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| 61 | *
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| 62 | * # Defined behavior
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| 63 | * * The function ticker_init is safe to call repeatedly - Verified by test ::ticker_init_test
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| 64 | * * The function ticker_init allows the ticker to keep counting and disables the ticker interrupt - Verified by test ::ticker_init_test
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| 65 | * * Ticker frequency is non-zero and counter is at least 8 bits - Verified by ::ticker_info_test
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| 66 | * * The ticker rolls over at (1 << bits) and continues counting starting from 0 - Verified by ::ticker_overflow_test
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| 67 | * * The ticker counts at the specified frequency +- 10% - Verified by ::ticker_frequency_test
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| 68 | * * The ticker increments by 1 each tick - Verified by ::ticker_increment_test
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| 69 | * * The ticker interrupt fires only when the ticker times increments to or past the value set by ticker_set_interrupt.
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| 70 | * Verified by ::ticker_interrupt_test and ::ticker_past_test
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| 71 | * * It is safe to call ticker_set_interrupt repeatedly before the handler is called - Verified by ::ticker_repeat_reschedule_test
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| 72 | * * The function ticker_fire_interrupt causes ticker_irq_handler to be called immediately from interrupt context -
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| 73 | * Verified by ::ticker_fire_now_test
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| 74 | * * The ticker operations ticker_read, ticker_clear_interrupt, ticker_set_interrupt and ticker_fire_interrupt
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| 75 | * take less than 20us to complete - Verified by ::ticker_speed_test
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| 76 | *
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| 77 | * # Undefined behavior
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| 78 | * * Calling any function other than ticker_init before the initialization of the ticker
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| 79 | * * Whether ticker_irq_handler is called a second time if the time wraps and matches the value set by ticker_set_interrupt again
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| 80 | * * Calling ticker_set_interrupt with a value that has more than the supported number of bits
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| 81 | * * Calling any function other than us_ticker_init after calling us_ticker_free
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| 82 | *
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| 83 | * # Potential bugs
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| 84 | * * Drift due to reschedule - Verified by ::ticker_repeat_reschedule_test
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| 85 | * * Incorrect overflow handling of timers - Verified by ::ticker_overflow_test
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| 86 | * * Interrupting at a time of 0 - Verified by ::ticker_overflow_test
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| 87 | * * Interrupt triggered more than once - Verified by ::ticker_interrupt_test
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| 88 | *
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| 89 | * @ingroup hal_us_ticker
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| 90 | * @ingroup hal_lp_ticker
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| 91 | */
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| 92 |
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| 93 | /**
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| 94 | * \defgroup hal_ticker_tests Ticker Tests
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| 95 | * Tests to validate the proper implementation of a ticker
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| 96 | *
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| 97 | * To run the ticker hal tests use the command:
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| 98 | *
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| 99 | * mbed test -t <toolchain> -m <target> -n tests-mbed_hal-common_ticker*
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| 100 | *
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| 101 | * @ingroup hal_us_ticker
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| 102 | * @ingroup hal_lp_ticker
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| 103 | */
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| 104 |
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| 105 |
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| 106 | typedef void (*ticker_irq_handler_type)(const ticker_data_t *const);
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| 107 |
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| 108 | /** Set ticker IRQ handler
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| 109 | *
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| 110 | * @param ticker_irq_handler IRQ handler to be connected
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| 111 | *
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| 112 | * @return previous ticker IRQ handler
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| 113 | *
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| 114 | * @note by default IRQ handler is set to ::ticker_irq_handler
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| 115 | * @note this function is primarily for testing purposes and it's not required part of HAL implementation
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| 116 | *
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| 117 | */
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| 118 | ticker_irq_handler_type set_us_ticker_irq_handler(ticker_irq_handler_type ticker_irq_handler);
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| 119 |
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[352] | 120 | /** Get ticker's data
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| 121 | *
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[374] | 122 | * @return The microsecond ticker data
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[352] | 123 | */
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[374] | 124 | const ticker_data_t *get_us_ticker_data(void);
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[352] | 125 |
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| 126 |
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| 127 | /** The wrapper for ticker_irq_handler, to pass us ticker's data
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| 128 | *
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| 129 | */
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| 130 | void us_ticker_irq_handler(void);
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| 131 |
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| 132 | /* HAL us ticker */
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| 133 |
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| 134 | /** Initialize the ticker
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| 135 | *
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[374] | 136 | * Initialize or re-initialize the ticker. This resets all the
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| 137 | * clocking and prescaler registers, along with disabling
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| 138 | * the compare interrupt.
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| 139 | *
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| 140 | * @note Initialization properties tested by ::ticker_init_test
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| 141 | *
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| 142 | * Pseudo Code:
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| 143 | * @code
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| 144 | * void us_ticker_init()
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| 145 | * {
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| 146 | * // Enable clock gate so processor can read TIMER registers
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| 147 | * POWER_CTRL |= POWER_CTRL_TIMER_Msk;
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| 148 | *
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| 149 | * // Disable the timer and ensure it is powered down
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| 150 | * TIMER_CTRL &= ~(TIMER_CTRL_ENABLE_Msk | TIMER_CTRL_COMPARE_ENABLE_Msk);
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| 151 | *
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| 152 | * // Configure divisors
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| 153 | * uint32_t prescale = SystemCoreClock / 1000000;
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| 154 | * TIMER_PRESCALE = prescale - 1;
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| 155 | * TIMER_CTRL |= TIMER_CTRL_ENABLE_Msk;
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| 156 | *
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| 157 | * // Install the interrupt handler
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| 158 | * NVIC_SetVector(TIMER_IRQn, (uint32_t)us_ticker_irq_handler);
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| 159 | * NVIC_EnableIRQ(TIMER_IRQn);
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| 160 | * }
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| 161 | * @endcode
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[352] | 162 | */
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| 163 | void us_ticker_init(void);
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| 164 |
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[374] | 165 | /** Deinitialize the us ticker
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| 166 | *
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| 167 | * Powerdown the us ticker in preparation for sleep, powerdown, or reset.
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| 168 | *
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| 169 | * After this function is called, no other ticker functions should be called
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| 170 | * except us_ticker_init(), calling any function other than init is undefined.
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| 171 | *
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| 172 | * @note This function stops the ticker from counting.
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| 173 | *
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| 174 | * Pseudo Code:
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| 175 | * @code
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| 176 | * uint32_t us_ticker_free()
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| 177 | * {
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| 178 | * // Disable timer
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| 179 | * TIMER_CTRL &= ~TIMER_CTRL_ENABLE_Msk;
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| 180 | *
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| 181 | * // Disable the compare interrupt
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| 182 | * TIMER_CTRL &= ~TIMER_CTRL_COMPARE_ENABLE_Msk;
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| 183 | *
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| 184 | * // Disable timer interrupt
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| 185 | * NVIC_DisableIRQ(TIMER_IRQn);
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| 186 | *
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| 187 | * // Disable clock gate so processor cannot read TIMER registers
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| 188 | * POWER_CTRL &= ~POWER_CTRL_TIMER_Msk;
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| 189 | * }
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| 190 | * @endcode
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| 191 | *
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| 192 | */
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| 193 | void us_ticker_free(void);
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| 194 |
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[352] | 195 | /** Read the current counter
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| 196 | *
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[374] | 197 | * Read the current counter value without performing frequency conversions.
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| 198 | * If no rollover has occurred, the seconds passed since us_ticker_init()
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| 199 | * was called can be found by dividing the ticks returned by this function
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| 200 | * by the frequency returned by ::us_ticker_get_info.
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| 201 | *
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| 202 | * @return The current timer's counter value in ticks
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| 203 | *
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| 204 | * Pseudo Code:
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| 205 | * @code
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| 206 | * uint32_t us_ticker_read()
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| 207 | * {
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| 208 | * return TIMER_COUNT;
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| 209 | * }
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| 210 | * @endcode
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[352] | 211 | */
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| 212 | uint32_t us_ticker_read(void);
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| 213 |
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| 214 | /** Set interrupt for specified timestamp
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| 215 | *
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[374] | 216 | * @param timestamp The time in ticks to be set
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| 217 | *
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| 218 | * @note no special handling needs to be done for times in the past
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| 219 | * as the common timer code will detect this and call
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| 220 | * us_ticker_fire_interrupt() if this is the case
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| 221 | *
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| 222 | * @note calling this function with timestamp of more than the supported
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| 223 | * number of bits returned by ::us_ticker_get_info results in undefined
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| 224 | * behavior.
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| 225 | *
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| 226 | * Pseudo Code:
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| 227 | * @code
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| 228 | * void us_ticker_set_interrupt(timestamp_t timestamp)
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| 229 | * {
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| 230 | * TIMER_COMPARE = timestamp;
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| 231 | * TIMER_CTRL |= TIMER_CTRL_COMPARE_ENABLE_Msk;
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| 232 | * }
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| 233 | * @endcode
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[352] | 234 | */
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| 235 | void us_ticker_set_interrupt(timestamp_t timestamp);
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| 236 |
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| 237 | /** Disable us ticker interrupt
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| 238 | *
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[374] | 239 | * Pseudo Code:
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| 240 | * @code
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| 241 | * void us_ticker_disable_interrupt(void)
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| 242 | * {
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| 243 | * // Disable the compare interrupt
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| 244 | * TIMER_CTRL &= ~TIMER_CTRL_COMPARE_ENABLE_Msk;
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| 245 | * }
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| 246 | * @endcode
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[352] | 247 | */
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| 248 | void us_ticker_disable_interrupt(void);
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| 249 |
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| 250 | /** Clear us ticker interrupt
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| 251 | *
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[374] | 252 | * Pseudo Code:
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| 253 | * @code
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| 254 | * void us_ticker_clear_interrupt(void)
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| 255 | * {
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| 256 | * // Write to the ICR (interrupt clear register) of the TIMER
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| 257 | * TIMER_ICR = TIMER_ICR_COMPARE_Msk;
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| 258 | * }
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| 259 | * @endcode
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[352] | 260 | */
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| 261 | void us_ticker_clear_interrupt(void);
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| 262 |
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[374] | 263 | /** Set pending interrupt that should be fired right away.
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| 264 | *
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| 265 | * The ticker should be initialized prior calling this function.
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| 266 | *
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| 267 | * Pseudo Code:
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| 268 | * @code
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| 269 | * void us_ticker_fire_interrupt(void)
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| 270 | * {
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| 271 | * NVIC_SetPendingIRQ(TIMER_IRQn);
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| 272 | * }
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| 273 | * @endcode
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| 274 | */
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| 275 | void us_ticker_fire_interrupt(void);
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| 276 |
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| 277 | /** Get frequency and counter bits of this ticker.
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| 278 | *
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| 279 | * Pseudo Code:
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| 280 | * @code
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| 281 | * const ticker_info_t* us_ticker_get_info()
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| 282 | * {
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| 283 | * static const ticker_info_t info = {
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| 284 | * 1000000, // 1 MHz
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| 285 | * 32 // 32 bit counter
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| 286 | * };
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| 287 | * return &info;
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| 288 | * }
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| 289 | * @endcode
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| 290 | */
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| 291 | const ticker_info_t *us_ticker_get_info(void);
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| 292 |
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[352] | 293 | /**@}*/
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| 294 |
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| 295 | #ifdef __cplusplus
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| 296 | }
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| 297 | #endif
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| 298 |
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| 299 | #endif
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| 300 |
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| 301 | /** @}*/
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