mirror of https://github.com/ARMmbed/mbed-os.git
113 lines
3.2 KiB
C
113 lines
3.2 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2018 GigaDevice Semiconductor Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#if DEVICE_RTC
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#include "rtc_api.h"
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static uint8_t rtc_init_flag = 0;
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/** Initialize the RTC peripheral
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*
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* Powerup the RTC in perpetration for access. This function must be called
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* before any other RTC functions ares called. This does not change the state
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* of the RTC. It just enables access to it.
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*
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* @note This function is safe to call repeatedly - Tested by ::rtc_init_test
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*/
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void rtc_init(void)
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{
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/* make sure RTC only init once */
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if (rtc_init_flag) {
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return;
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}
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rtc_init_flag = 1;
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/* enable PMU and BKPI clocks */
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rcu_periph_clock_enable(RCU_BKPI);
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rcu_periph_clock_enable(RCU_PMU);
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/* allow access to BKP domain */
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pmu_backup_write_enable();
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/* enable LXTAL */
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rcu_osci_on(RCU_LXTAL);
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/* wait till LXTAL is ready */
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rcu_osci_stab_wait(RCU_LXTAL);
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/* select RCU_LXTAL as RTC clock source */
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rcu_rtc_clock_config(RCU_RTCSRC_LXTAL);
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/* enable RTC Clock */
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rcu_periph_clock_enable(RCU_RTC);
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/* wait for RTC registers synchronization */
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rtc_register_sync_wait();
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/* wait until last write operation on RTC registers has finished */
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rtc_lwoff_wait();
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/* set RTC prescaler: set RTC period to 1s */
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rtc_prescaler_set(32767);
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/* wait until last write operation on RTC registers has finished */
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rtc_lwoff_wait();
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}
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/** Deinitialize RTC
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*
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* Powerdown the RTC in preparation for sleep, powerdown or reset. That should only
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* affect the CPU domain and not the time keeping logic.
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* After this function is called no other RTC functions should be called
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* except for ::rtc_init.
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*/
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void rtc_free(void)
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{
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}
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/** Check if the RTC has the time set and is counting
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*
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* @retval 0 The time reported by the RTC is not valid
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* @retval 1 The time has been set the RTC is counting
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*/
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int rtc_isenabled(void)
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{
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if (RESET == (RTC_CTL & RTC_CTL_RSYNF)) {
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return 0;
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} else {
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return 1;
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}
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}
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/** Get the current time from the RTC peripheral
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*
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* @return The current time in seconds
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*
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* @note Some RTCs are not synchronized with the main clock. If
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* this is the case with your RTC then you must read the RTC time
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* in a loop to prevent reading the wrong time due to a glitch.
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* The test ::rtc_glitch_test is intended to catch this bug.
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*/
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time_t rtc_read(void)
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{
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return (rtc_counter_get());
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}
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/** Write the current time in seconds to the RTC peripheral
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*
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* @param t The current time to be set in seconds.
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*/
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void rtc_write(time_t t)
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{
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rtc_counter_set((uint32_t)t);
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rtc_lwoff_wait();
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}
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#endif /* DEVICE_RTC */
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