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mbed 2

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hal/rtc_api.h@169:a7c7b631e539, 2018-06-22 (annotated)

Committer:
Anna Bridge
Date:
Fri Jun 22 15:38:59 2018 +0100
Revision:
169:a7c7b631e539
Parent:
128:9bcdf88f62b0
Child:
172:65be27845400
mbed library. Release version 162

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