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cmsis/BUILD/mbed/hal/rtc_api.h@189:f392fc9709a3, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 22:31:08 2019 +0000
Revision:
189:f392fc9709a3
mbed library release version 165

Who changed what in which revision?

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AnnaBridge 189:f392fc9709a3 1 /* mbed Microcontroller Library
AnnaBridge 189:f392fc9709a3 2 * Copyright (c) 2006-2013 ARM Limited
AnnaBridge 189:f392fc9709a3 3 * SPDX-License-Identifier: Apache-2.0
AnnaBridge 189:f392fc9709a3 4 *
AnnaBridge 189:f392fc9709a3 5 * Licensed under the Apache License, Version 2.0 (the "License");
AnnaBridge 189:f392fc9709a3 6 * you may not use this file except in compliance with the License.
AnnaBridge 189:f392fc9709a3 7 * You may obtain a copy of the License at
AnnaBridge 189:f392fc9709a3 8 *
AnnaBridge 189:f392fc9709a3 9 * http://www.apache.org/licenses/LICENSE-2.0
AnnaBridge 189:f392fc9709a3 10 *
AnnaBridge 189:f392fc9709a3 11 * Unless required by applicable law or agreed to in writing, software
AnnaBridge 189:f392fc9709a3 12 * distributed under the License is distributed on an "AS IS" BASIS,
AnnaBridge 189:f392fc9709a3 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
AnnaBridge 189:f392fc9709a3 14 * See the License for the specific language governing permissions and
AnnaBridge 189:f392fc9709a3 15 * limitations under the License.
AnnaBridge 189:f392fc9709a3 16 */
AnnaBridge 189:f392fc9709a3 17
AnnaBridge 189:f392fc9709a3 18 /** \addtogroup hal */
AnnaBridge 189:f392fc9709a3 19 /** @{*/
AnnaBridge 189:f392fc9709a3 20
AnnaBridge 189:f392fc9709a3 21 #ifndef MBED_RTC_API_H
AnnaBridge 189:f392fc9709a3 22 #define MBED_RTC_API_H
AnnaBridge 189:f392fc9709a3 23
AnnaBridge 189:f392fc9709a3 24 #include "device.h"
AnnaBridge 189:f392fc9709a3 25
AnnaBridge 189:f392fc9709a3 26 #include <time.h>
AnnaBridge 189:f392fc9709a3 27
AnnaBridge 189:f392fc9709a3 28 #ifdef __cplusplus
AnnaBridge 189:f392fc9709a3 29 extern "C" {
AnnaBridge 189:f392fc9709a3 30 #endif
AnnaBridge 189:f392fc9709a3 31
AnnaBridge 189:f392fc9709a3 32 /**
AnnaBridge 189:f392fc9709a3 33 * \defgroup hal_rtc RTC hal
AnnaBridge 189:f392fc9709a3 34 *
AnnaBridge 189:f392fc9709a3 35 * The RTC hal provides a low level interface to the Real Time Counter (RTC) of a
AnnaBridge 189:f392fc9709a3 36 * target.
AnnaBridge 189:f392fc9709a3 37 *
AnnaBridge 189:f392fc9709a3 38 * # Defined behaviour
AnnaBridge 189:f392fc9709a3 39 * * The function ::rtc_init is safe to call repeatedly - Verified by test ::rtc_init_test.
AnnaBridge 189:f392fc9709a3 40 * * RTC accuracy is at least 10% - Verified by test ::rtc_accuracy_test.
AnnaBridge 189:f392fc9709a3 41 * * Init/free doesn't stop RTC from counting - Verified by test ::rtc_persist_test.
AnnaBridge 189:f392fc9709a3 42 * * Software reset doesn't stop RTC from counting - Verified by test ::rtc_reset_test.
AnnaBridge 189:f392fc9709a3 43 * * Sleep modes don't stop RTC from counting - Verified by test ::rtc_sleep_test.
AnnaBridge 189:f392fc9709a3 44 * * Shutdown mode doesn't stop RTC from counting - Not verified.
AnnaBridge 189:f392fc9709a3 45 * * The functions ::rtc_write/::rtc_read provides availability to set/get RTC time
AnnaBridge 189:f392fc9709a3 46 * - Verified by test ::rtc_write_read_test.
AnnaBridge 189:f392fc9709a3 47 * * The functions ::rtc_isenabled returns 1 if the RTC is counting and the time has been set,
AnnaBridge 189:f392fc9709a3 48 * 0 otherwise - Verified by test ::rtc_enabled_test.
AnnaBridge 189:f392fc9709a3 49 *
AnnaBridge 189:f392fc9709a3 50 * # Undefined behaviour
AnnaBridge 189:f392fc9709a3 51 * * Calling any function other than ::rtc_init before the initialisation of the RTC
AnnaBridge 189:f392fc9709a3 52 *
AnnaBridge 189:f392fc9709a3 53 * # Potential bugs
AnnaBridge 189:f392fc9709a3 54 * * Incorrect overflow handling - Verified by ::rtc_range_test
AnnaBridge 189:f392fc9709a3 55 * * Glitches due to ripple counter - Verified by ::rtc_glitch_test
AnnaBridge 189:f392fc9709a3 56 *
AnnaBridge 189:f392fc9709a3 57 * @see hal_rtc_tests
AnnaBridge 189:f392fc9709a3 58 *
AnnaBridge 189:f392fc9709a3 59 * @{
AnnaBridge 189:f392fc9709a3 60 */
AnnaBridge 189:f392fc9709a3 61
AnnaBridge 189:f392fc9709a3 62 /**
AnnaBridge 189:f392fc9709a3 63 * \defgroup hal_rtc_tests RTC hal tests
AnnaBridge 189:f392fc9709a3 64 * The RTC test validate proper implementation of the RTC hal.
AnnaBridge 189:f392fc9709a3 65 *
AnnaBridge 189:f392fc9709a3 66 * To run the RTC hal tests use the command:
AnnaBridge 189:f392fc9709a3 67 *
AnnaBridge 189:f392fc9709a3 68 * mbed test -t <toolchain> -m <target> -n tests-mbed_hal-rtc*
AnnaBridge 189:f392fc9709a3 69 */
AnnaBridge 189:f392fc9709a3 70
AnnaBridge 189:f392fc9709a3 71
AnnaBridge 189:f392fc9709a3 72 /** Initialize the RTC peripheral
AnnaBridge 189:f392fc9709a3 73 *
AnnaBridge 189:f392fc9709a3 74 * Powerup the RTC in perpetration for access. This function must be called
AnnaBridge 189:f392fc9709a3 75 * before any other RTC functions ares called. This does not change the state
AnnaBridge 189:f392fc9709a3 76 * of the RTC. It just enables access to it.
AnnaBridge 189:f392fc9709a3 77 *
AnnaBridge 189:f392fc9709a3 78 * @note This function is safe to call repeatedly - Tested by ::rtc_init_test
AnnaBridge 189:f392fc9709a3 79 *
AnnaBridge 189:f392fc9709a3 80 * Example Implementation Pseudo Code:
AnnaBridge 189:f392fc9709a3 81 * @code
AnnaBridge 189:f392fc9709a3 82 * void rtc_init()
AnnaBridge 189:f392fc9709a3 83 * {
AnnaBridge 189:f392fc9709a3 84 * // Enable clock gate so processor can read RTC registers
AnnaBridge 189:f392fc9709a3 85 * POWER_CTRL |= POWER_CTRL_RTC_Msk;
AnnaBridge 189:f392fc9709a3 86 *
AnnaBridge 189:f392fc9709a3 87 * // See if the RTC is already setup
AnnaBridge 189:f392fc9709a3 88 * if (!(RTC_STATUS & RTC_STATUS_COUNTING_Msk)) {
AnnaBridge 189:f392fc9709a3 89 *
AnnaBridge 189:f392fc9709a3 90 * // Setup the RTC clock source
AnnaBridge 189:f392fc9709a3 91 * RTC_CTRL |= RTC_CTRL_CLK32_Msk;
AnnaBridge 189:f392fc9709a3 92 * }
AnnaBridge 189:f392fc9709a3 93 * }
AnnaBridge 189:f392fc9709a3 94 * @endcode
AnnaBridge 189:f392fc9709a3 95 */
AnnaBridge 189:f392fc9709a3 96 void rtc_init(void);
AnnaBridge 189:f392fc9709a3 97
AnnaBridge 189:f392fc9709a3 98 /** Deinitialize RTC
AnnaBridge 189:f392fc9709a3 99 *
AnnaBridge 189:f392fc9709a3 100 * Powerdown the RTC in preparation for sleep, powerdown or reset. That should only
AnnaBridge 189:f392fc9709a3 101 * affect the CPU domain and not the time keeping logic.
AnnaBridge 189:f392fc9709a3 102 * After this function is called no other RTC functions should be called
AnnaBridge 189:f392fc9709a3 103 * except for ::rtc_init.
AnnaBridge 189:f392fc9709a3 104 *
AnnaBridge 189:f392fc9709a3 105 * @note This function does not stop the RTC from counting - Tested by ::rtc_persist_test
AnnaBridge 189:f392fc9709a3 106 *
AnnaBridge 189:f392fc9709a3 107 * Example Implementation Pseudo Code:
AnnaBridge 189:f392fc9709a3 108 * @code
AnnaBridge 189:f392fc9709a3 109 * void rtc_free()
AnnaBridge 189:f392fc9709a3 110 * {
AnnaBridge 189:f392fc9709a3 111 * // Disable clock gate since processor no longer needs to read RTC registers
AnnaBridge 189:f392fc9709a3 112 * POWER_CTRL &= ~POWER_CTRL_RTC_Msk;
AnnaBridge 189:f392fc9709a3 113 * }
AnnaBridge 189:f392fc9709a3 114 * @endcode
AnnaBridge 189:f392fc9709a3 115 */
AnnaBridge 189:f392fc9709a3 116 void rtc_free(void);
AnnaBridge 189:f392fc9709a3 117
AnnaBridge 189:f392fc9709a3 118 /** Check if the RTC has the time set and is counting
AnnaBridge 189:f392fc9709a3 119 *
AnnaBridge 189:f392fc9709a3 120 * @retval 0 The time reported by the RTC is not valid
AnnaBridge 189:f392fc9709a3 121 * @retval 1 The time has been set the RTC is counting
AnnaBridge 189:f392fc9709a3 122 *
AnnaBridge 189:f392fc9709a3 123 * Example Implementation Pseudo Code:
AnnaBridge 189:f392fc9709a3 124 * @code
AnnaBridge 189:f392fc9709a3 125 * int rtc_isenabled()
AnnaBridge 189:f392fc9709a3 126 * {
AnnaBridge 189:f392fc9709a3 127 * if (RTC_STATUS & RTC_STATUS_COUNTING_Msk) {
AnnaBridge 189:f392fc9709a3 128 * return 1;
AnnaBridge 189:f392fc9709a3 129 * } else {
AnnaBridge 189:f392fc9709a3 130 * return 0;
AnnaBridge 189:f392fc9709a3 131 * }
AnnaBridge 189:f392fc9709a3 132 * }
AnnaBridge 189:f392fc9709a3 133 * @endcode
AnnaBridge 189:f392fc9709a3 134 */
AnnaBridge 189:f392fc9709a3 135 int rtc_isenabled(void);
AnnaBridge 189:f392fc9709a3 136
AnnaBridge 189:f392fc9709a3 137 /** Get the current time from the RTC peripheral
AnnaBridge 189:f392fc9709a3 138 *
AnnaBridge 189:f392fc9709a3 139 * @return The current time in seconds
AnnaBridge 189:f392fc9709a3 140 *
AnnaBridge 189:f392fc9709a3 141 * @note Some RTCs are not synchronized with the main clock. If
AnnaBridge 189:f392fc9709a3 142 * this is the case with your RTC then you must read the RTC time
AnnaBridge 189:f392fc9709a3 143 * in a loop to prevent reading the wrong time due to a glitch.
AnnaBridge 189:f392fc9709a3 144 * The test ::rtc_glitch_test is intended to catch this bug.
AnnaBridge 189:f392fc9709a3 145 *
AnnaBridge 189:f392fc9709a3 146 * Example implementation for an unsynchronized ripple counter:
AnnaBridge 189:f392fc9709a3 147 * @code
AnnaBridge 189:f392fc9709a3 148 * time_t rtc_read()
AnnaBridge 189:f392fc9709a3 149 * {
AnnaBridge 189:f392fc9709a3 150 * uint32_t val;
AnnaBridge 189:f392fc9709a3 151 * uint32_t last_val;
AnnaBridge 189:f392fc9709a3 152 *
AnnaBridge 189:f392fc9709a3 153 * // Loop until the same value is read twice
AnnaBridge 189:f392fc9709a3 154 * val = RTC_SECONDS;
AnnaBridge 189:f392fc9709a3 155 * do {
AnnaBridge 189:f392fc9709a3 156 * last_val = val;
AnnaBridge 189:f392fc9709a3 157 * val = RTC_SECONDS;
AnnaBridge 189:f392fc9709a3 158 * } while (last_val != val);
AnnaBridge 189:f392fc9709a3 159 *
AnnaBridge 189:f392fc9709a3 160 * return (time_t)val;
AnnaBridge 189:f392fc9709a3 161 * }
AnnaBridge 189:f392fc9709a3 162 * @endcode
AnnaBridge 189:f392fc9709a3 163 */
AnnaBridge 189:f392fc9709a3 164 time_t rtc_read(void);
AnnaBridge 189:f392fc9709a3 165
AnnaBridge 189:f392fc9709a3 166 /** Write the current time in seconds to the RTC peripheral
AnnaBridge 189:f392fc9709a3 167 *
AnnaBridge 189:f392fc9709a3 168 * @param t The current time to be set in seconds.
AnnaBridge 189:f392fc9709a3 169 *
AnnaBridge 189:f392fc9709a3 170 * Example Implementation Pseudo Code:
AnnaBridge 189:f392fc9709a3 171 * @code
AnnaBridge 189:f392fc9709a3 172 * void rtc_write(time_t t)
AnnaBridge 189:f392fc9709a3 173 * {
AnnaBridge 189:f392fc9709a3 174 * RTC_SECONDS = t;
AnnaBridge 189:f392fc9709a3 175 * }
AnnaBridge 189:f392fc9709a3 176 * @endcode
AnnaBridge 189:f392fc9709a3 177 */
AnnaBridge 189:f392fc9709a3 178 void rtc_write(time_t t);
AnnaBridge 189:f392fc9709a3 179
AnnaBridge 189:f392fc9709a3 180 /**@}*/
AnnaBridge 189:f392fc9709a3 181
AnnaBridge 189:f392fc9709a3 182 #ifdef __cplusplus
AnnaBridge 189:f392fc9709a3 183 }
AnnaBridge 189:f392fc9709a3 184 #endif
AnnaBridge 189:f392fc9709a3 185
AnnaBridge 189:f392fc9709a3 186 #endif
AnnaBridge 189:f392fc9709a3 187
AnnaBridge 189:f392fc9709a3 188 /** @}*/