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hal/rtc_api.h@172:65be27845400, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 20:53:29 2019 +0000
Revision:
172:65be27845400
Parent:
169:a7c7b631e539 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 128:9bcdf88f62b0 1 /* mbed Microcontroller Library
<> 128:9bcdf88f62b0 2 * Copyright (c) 2006-2013 ARM Limited
AnnaBridge 172:65be27845400 3 * SPDX-License-Identifier: Apache-2.0
<> 128:9bcdf88f62b0 4 *
<> 128:9bcdf88f62b0 5 * Licensed under the Apache License, Version 2.0 (the "License");
<> 128:9bcdf88f62b0 6 * you may not use this file except in compliance with the License.
<> 128:9bcdf88f62b0 7 * You may obtain a copy of the License at
<> 128:9bcdf88f62b0 8 *
<> 128:9bcdf88f62b0 9 * http://www.apache.org/licenses/LICENSE-2.0
<> 128:9bcdf88f62b0 10 *
<> 128:9bcdf88f62b0 11 * Unless required by applicable law or agreed to in writing, software
<> 128:9bcdf88f62b0 12 * distributed under the License is distributed on an "AS IS" BASIS,
<> 128:9bcdf88f62b0 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 128:9bcdf88f62b0 14 * See the License for the specific language governing permissions and
<> 128:9bcdf88f62b0 15 * limitations under the License.
<> 128:9bcdf88f62b0 16 */
Anna Bridge 169:a7c7b631e539 17
Anna Bridge 169:a7c7b631e539 18 /** \addtogroup hal */
Anna Bridge 169:a7c7b631e539 19 /** @{*/
Anna Bridge 169:a7c7b631e539 20
<> 128:9bcdf88f62b0 21 #ifndef MBED_RTC_API_H
<> 128:9bcdf88f62b0 22 #define MBED_RTC_API_H
<> 128:9bcdf88f62b0 23
<> 128:9bcdf88f62b0 24 #include "device.h"
<> 128:9bcdf88f62b0 25
<> 128:9bcdf88f62b0 26 #include <time.h>
<> 128:9bcdf88f62b0 27
<> 128:9bcdf88f62b0 28 #ifdef __cplusplus
<> 128:9bcdf88f62b0 29 extern "C" {
<> 128:9bcdf88f62b0 30 #endif
<> 128:9bcdf88f62b0 31
<> 128:9bcdf88f62b0 32 /**
Anna Bridge 169:a7c7b631e539 33 * \defgroup hal_rtc RTC hal
Anna Bridge 169:a7c7b631e539 34 *
Anna Bridge 169:a7c7b631e539 35 * The RTC hal provides a low level interface to the Real Time Counter (RTC) of a
Anna Bridge 169:a7c7b631e539 36 * target.
Anna Bridge 169:a7c7b631e539 37 *
Anna Bridge 169:a7c7b631e539 38 * # Defined behaviour
Anna Bridge 169:a7c7b631e539 39 * * The function ::rtc_init is safe to call repeatedly - Verified by test ::rtc_init_test.
Anna Bridge 169:a7c7b631e539 40 * * RTC accuracy is at least 10% - Verified by test ::rtc_accuracy_test.
Anna Bridge 169:a7c7b631e539 41 * * Init/free doesn't stop RTC from counting - Verified by test ::rtc_persist_test.
Anna Bridge 169:a7c7b631e539 42 * * Software reset doesn't stop RTC from counting - Verified by test ::rtc_reset_test.
Anna Bridge 169:a7c7b631e539 43 * * Sleep modes don't stop RTC from counting - Verified by test ::rtc_sleep_test.
Anna Bridge 169:a7c7b631e539 44 * * Shutdown mode doesn't stop RTC from counting - Not verified.
Anna Bridge 169:a7c7b631e539 45 * * The functions ::rtc_write/::rtc_read provides availability to set/get RTC time
Anna Bridge 169:a7c7b631e539 46 * - Verified by test ::rtc_write_read_test.
Anna Bridge 169:a7c7b631e539 47 * * The functions ::rtc_isenabled returns 1 if the RTC is counting and the time has been set,
Anna Bridge 169:a7c7b631e539 48 * 0 otherwise - Verified by test ::rtc_enabled_test.
Anna Bridge 169:a7c7b631e539 49 *
Anna Bridge 169:a7c7b631e539 50 * # Undefined behaviour
Anna Bridge 169:a7c7b631e539 51 * * Calling any function other than ::rtc_init before the initialisation of the RTC
Anna Bridge 169:a7c7b631e539 52 *
Anna Bridge 169:a7c7b631e539 53 * # Potential bugs
Anna Bridge 169:a7c7b631e539 54 * * Incorrect overflow handling - Verified by ::rtc_range_test
Anna Bridge 169:a7c7b631e539 55 * * Glitches due to ripple counter - Verified by ::rtc_glitch_test
Anna Bridge 169:a7c7b631e539 56 *
Anna Bridge 169:a7c7b631e539 57 * @see hal_rtc_tests
Anna Bridge 169:a7c7b631e539 58 *
<> 128:9bcdf88f62b0 59 * @{
<> 128:9bcdf88f62b0 60 */
<> 128:9bcdf88f62b0 61
Anna Bridge 169:a7c7b631e539 62 /**
Anna Bridge 169:a7c7b631e539 63 * \defgroup hal_rtc_tests RTC hal tests
Anna Bridge 169:a7c7b631e539 64 * The RTC test validate proper implementation of the RTC hal.
Anna Bridge 169:a7c7b631e539 65 *
Anna Bridge 169:a7c7b631e539 66 * To run the RTC hal tests use the command:
Anna Bridge 169:a7c7b631e539 67 *
Anna Bridge 169:a7c7b631e539 68 * mbed test -t <toolchain> -m <target> -n tests-mbed_hal-rtc*
Anna Bridge 169:a7c7b631e539 69 */
Anna Bridge 169:a7c7b631e539 70
Anna Bridge 169:a7c7b631e539 71
<> 128:9bcdf88f62b0 72 /** Initialize the RTC peripheral
<> 128:9bcdf88f62b0 73 *
Anna Bridge 169:a7c7b631e539 74 * Powerup the RTC in perpetration for access. This function must be called
Anna Bridge 169:a7c7b631e539 75 * before any other RTC functions ares called. This does not change the state
Anna Bridge 169:a7c7b631e539 76 * of the RTC. It just enables access to it.
Anna Bridge 169:a7c7b631e539 77 *
Anna Bridge 169:a7c7b631e539 78 * @note This function is safe to call repeatedly - Tested by ::rtc_init_test
Anna Bridge 169:a7c7b631e539 79 *
Anna Bridge 169:a7c7b631e539 80 * Example Implementation Pseudo Code:
Anna Bridge 169:a7c7b631e539 81 * @code
Anna Bridge 169:a7c7b631e539 82 * void rtc_init()
Anna Bridge 169:a7c7b631e539 83 * {
Anna Bridge 169:a7c7b631e539 84 * // Enable clock gate so processor can read RTC registers
Anna Bridge 169:a7c7b631e539 85 * POWER_CTRL |= POWER_CTRL_RTC_Msk;
Anna Bridge 169:a7c7b631e539 86 *
Anna Bridge 169:a7c7b631e539 87 * // See if the RTC is already setup
Anna Bridge 169:a7c7b631e539 88 * if (!(RTC_STATUS & RTC_STATUS_COUNTING_Msk)) {
Anna Bridge 169:a7c7b631e539 89 *
Anna Bridge 169:a7c7b631e539 90 * // Setup the RTC clock source
Anna Bridge 169:a7c7b631e539 91 * RTC_CTRL |= RTC_CTRL_CLK32_Msk;
Anna Bridge 169:a7c7b631e539 92 * }
Anna Bridge 169:a7c7b631e539 93 * }
Anna Bridge 169:a7c7b631e539 94 * @endcode
<> 128:9bcdf88f62b0 95 */
<> 128:9bcdf88f62b0 96 void rtc_init(void);
<> 128:9bcdf88f62b0 97
<> 128:9bcdf88f62b0 98 /** Deinitialize RTC
<> 128:9bcdf88f62b0 99 *
Anna Bridge 169:a7c7b631e539 100 * Powerdown the RTC in preparation for sleep, powerdown or reset. That should only
Anna Bridge 169:a7c7b631e539 101 * affect the CPU domain and not the time keeping logic.
Anna Bridge 169:a7c7b631e539 102 * After this function is called no other RTC functions should be called
Anna Bridge 169:a7c7b631e539 103 * except for ::rtc_init.
Anna Bridge 169:a7c7b631e539 104 *
Anna Bridge 169:a7c7b631e539 105 * @note This function does not stop the RTC from counting - Tested by ::rtc_persist_test
Anna Bridge 169:a7c7b631e539 106 *
Anna Bridge 169:a7c7b631e539 107 * Example Implementation Pseudo Code:
Anna Bridge 169:a7c7b631e539 108 * @code
Anna Bridge 169:a7c7b631e539 109 * void rtc_free()
Anna Bridge 169:a7c7b631e539 110 * {
Anna Bridge 169:a7c7b631e539 111 * // Disable clock gate since processor no longer needs to read RTC registers
Anna Bridge 169:a7c7b631e539 112 * POWER_CTRL &= ~POWER_CTRL_RTC_Msk;
Anna Bridge 169:a7c7b631e539 113 * }
Anna Bridge 169:a7c7b631e539 114 * @endcode
<> 128:9bcdf88f62b0 115 */
<> 128:9bcdf88f62b0 116 void rtc_free(void);
<> 128:9bcdf88f62b0 117
Anna Bridge 169:a7c7b631e539 118 /** Check if the RTC has the time set and is counting
Anna Bridge 169:a7c7b631e539 119 *
Anna Bridge 169:a7c7b631e539 120 * @retval 0 The time reported by the RTC is not valid
Anna Bridge 169:a7c7b631e539 121 * @retval 1 The time has been set the RTC is counting
<> 128:9bcdf88f62b0 122 *
Anna Bridge 169:a7c7b631e539 123 * Example Implementation Pseudo Code:
Anna Bridge 169:a7c7b631e539 124 * @code
Anna Bridge 169:a7c7b631e539 125 * int rtc_isenabled()
Anna Bridge 169:a7c7b631e539 126 * {
Anna Bridge 169:a7c7b631e539 127 * if (RTC_STATUS & RTC_STATUS_COUNTING_Msk) {
Anna Bridge 169:a7c7b631e539 128 * return 1;
Anna Bridge 169:a7c7b631e539 129 * } else {
Anna Bridge 169:a7c7b631e539 130 * return 0;
Anna Bridge 169:a7c7b631e539 131 * }
Anna Bridge 169:a7c7b631e539 132 * }
Anna Bridge 169:a7c7b631e539 133 * @endcode
<> 128:9bcdf88f62b0 134 */
<> 128:9bcdf88f62b0 135 int rtc_isenabled(void);
<> 128:9bcdf88f62b0 136
<> 128:9bcdf88f62b0 137 /** Get the current time from the RTC peripheral
<> 128:9bcdf88f62b0 138 *
Anna Bridge 169:a7c7b631e539 139 * @return The current time in seconds
Anna Bridge 169:a7c7b631e539 140 *
Anna Bridge 169:a7c7b631e539 141 * @note Some RTCs are not synchronized with the main clock. If
Anna Bridge 169:a7c7b631e539 142 * this is the case with your RTC then you must read the RTC time
Anna Bridge 169:a7c7b631e539 143 * in a loop to prevent reading the wrong time due to a glitch.
Anna Bridge 169:a7c7b631e539 144 * The test ::rtc_glitch_test is intended to catch this bug.
Anna Bridge 169:a7c7b631e539 145 *
Anna Bridge 169:a7c7b631e539 146 * Example implementation for an unsynchronized ripple counter:
Anna Bridge 169:a7c7b631e539 147 * @code
Anna Bridge 169:a7c7b631e539 148 * time_t rtc_read()
Anna Bridge 169:a7c7b631e539 149 * {
Anna Bridge 169:a7c7b631e539 150 * uint32_t val;
Anna Bridge 169:a7c7b631e539 151 * uint32_t last_val;
Anna Bridge 169:a7c7b631e539 152 *
Anna Bridge 169:a7c7b631e539 153 * // Loop until the same value is read twice
Anna Bridge 169:a7c7b631e539 154 * val = RTC_SECONDS;
Anna Bridge 169:a7c7b631e539 155 * do {
Anna Bridge 169:a7c7b631e539 156 * last_val = val;
Anna Bridge 169:a7c7b631e539 157 * val = RTC_SECONDS;
Anna Bridge 169:a7c7b631e539 158 * } while (last_val != val);
Anna Bridge 169:a7c7b631e539 159 *
Anna Bridge 169:a7c7b631e539 160 * return (time_t)val;
Anna Bridge 169:a7c7b631e539 161 * }
Anna Bridge 169:a7c7b631e539 162 * @endcode
<> 128:9bcdf88f62b0 163 */
<> 128:9bcdf88f62b0 164 time_t rtc_read(void);
<> 128:9bcdf88f62b0 165
Anna Bridge 169:a7c7b631e539 166 /** Write the current time in seconds to the RTC peripheral
Anna Bridge 169:a7c7b631e539 167 *
Anna Bridge 169:a7c7b631e539 168 * @param t The current time to be set in seconds.
<> 128:9bcdf88f62b0 169 *
Anna Bridge 169:a7c7b631e539 170 * Example Implementation Pseudo Code:
Anna Bridge 169:a7c7b631e539 171 * @code
Anna Bridge 169:a7c7b631e539 172 * void rtc_write(time_t t)
Anna Bridge 169:a7c7b631e539 173 * {
Anna Bridge 169:a7c7b631e539 174 * RTC_SECONDS = t;
Anna Bridge 169:a7c7b631e539 175 * }
Anna Bridge 169:a7c7b631e539 176 * @endcode
<> 128:9bcdf88f62b0 177 */
<> 128:9bcdf88f62b0 178 void rtc_write(time_t t);
<> 128:9bcdf88f62b0 179
<> 128:9bcdf88f62b0 180 /**@}*/
<> 128:9bcdf88f62b0 181
<> 128:9bcdf88f62b0 182 #ifdef __cplusplus
<> 128:9bcdf88f62b0 183 }
<> 128:9bcdf88f62b0 184 #endif
<> 128:9bcdf88f62b0 185
<> 128:9bcdf88f62b0 186 #endif
<> 128:9bcdf88f62b0 187
<> 128:9bcdf88f62b0 188 /** @}*/