RTC auf true
hal/rtc_api.h
- Committer:
- kevman
- Date:
- 2018-11-28
- Revision:
- 0:38ceb79fef03
File content as of revision 0:38ceb79fef03:
/* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /** \addtogroup hal */ /** @{*/ #ifndef MBED_RTC_API_H #define MBED_RTC_API_H #include "device.h" #include <time.h> #ifdef __cplusplus extern "C" { #endif /** * \defgroup hal_rtc RTC hal * * The RTC hal provides a low level interface to the Real Time Counter (RTC) of a * target. * * # Defined behaviour * * The function ::rtc_init is safe to call repeatedly - Verified by test ::rtc_init_test. * * RTC accuracy is at least 10% - Verified by test ::rtc_accuracy_test. * * Init/free doesn't stop RTC from counting - Verified by test ::rtc_persist_test. * * Software reset doesn't stop RTC from counting - Verified by test ::rtc_reset_test. * * Sleep modes don't stop RTC from counting - Verified by test ::rtc_sleep_test. * * Shutdown mode doesn't stop RTC from counting - Not verified. * * The functions ::rtc_write/::rtc_read provides availability to set/get RTC time * - Verified by test ::rtc_write_read_test. * * The functions ::rtc_isenabled returns 1 if the RTC is counting and the time has been set, * 0 otherwise - Verified by test ::rtc_enabled_test. * * # Undefined behaviour * * Calling any function other than ::rtc_init before the initialisation of the RTC * * # Potential bugs * * Incorrect overflow handling - Verified by ::rtc_range_test * * Glitches due to ripple counter - Verified by ::rtc_glitch_test * * @see hal_rtc_tests * * @{ */ /** * \defgroup hal_rtc_tests RTC hal tests * The RTC test validate proper implementation of the RTC hal. * * To run the RTC hal tests use the command: * * mbed test -t <toolchain> -m <target> -n tests-mbed_hal-rtc* */ /** Initialize the RTC peripheral * * Powerup the RTC in perpetration for access. This function must be called * before any other RTC functions ares called. This does not change the state * of the RTC. It just enables access to it. * * @note This function is safe to call repeatedly - Tested by ::rtc_init_test * * Example Implementation Pseudo Code: * @code * void rtc_init() * { * // Enable clock gate so processor can read RTC registers * POWER_CTRL |= POWER_CTRL_RTC_Msk; * * // See if the RTC is already setup * if (!(RTC_STATUS & RTC_STATUS_COUNTING_Msk)) { * * // Setup the RTC clock source * RTC_CTRL |= RTC_CTRL_CLK32_Msk; * } * } * @endcode */ void rtc_init(void); /** Deinitialize RTC * * Powerdown the RTC in preparation for sleep, powerdown or reset. That should only * affect the CPU domain and not the time keeping logic. * After this function is called no other RTC functions should be called * except for ::rtc_init. * * @note This function does not stop the RTC from counting - Tested by ::rtc_persist_test * * Example Implementation Pseudo Code: * @code * void rtc_free() * { * // Disable clock gate since processor no longer needs to read RTC registers * POWER_CTRL &= ~POWER_CTRL_RTC_Msk; * } * @endcode */ void rtc_free(void); /** Check if the RTC has the time set and is counting * * @retval 0 The time reported by the RTC is not valid * @retval 1 The time has been set the RTC is counting * * Example Implementation Pseudo Code: * @code * int rtc_isenabled() * { * if (RTC_STATUS & RTC_STATUS_COUNTING_Msk) { * return 1; * } else { * return 0; * } * } * @endcode */ int rtc_isenabled(void); /** Get the current time from the RTC peripheral * * @return The current time in seconds * * @note Some RTCs are not synchronized with the main clock. If * this is the case with your RTC then you must read the RTC time * in a loop to prevent reading the wrong time due to a glitch. * The test ::rtc_glitch_test is intended to catch this bug. * * Example implementation for an unsynchronized ripple counter: * @code * time_t rtc_read() * { * uint32_t val; * uint32_t last_val; * * // Loop until the same value is read twice * val = RTC_SECONDS; * do { * last_val = val; * val = RTC_SECONDS; * } while (last_val != val); * * return (time_t)val; * } * @endcode */ time_t rtc_read(void); /** Write the current time in seconds to the RTC peripheral * * @param t The current time to be set in seconds. * * Example Implementation Pseudo Code: * @code * void rtc_write(time_t t) * { * RTC_SECONDS = t; * } * @endcode */ void rtc_write(time_t t); /**@}*/ #ifdef __cplusplus } #endif #endif /** @}*/