mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

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targets/TARGET_GigaDevice/TARGET_GD32F30X/rtc_api.c@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?

UserRevisionLine numberNew contents of line
AnnaBridge 189:f392fc9709a3 1 /* mbed Microcontroller Library
AnnaBridge 189:f392fc9709a3 2 * Copyright (c) 2018 GigaDevice Semiconductor Inc.
AnnaBridge 189:f392fc9709a3 3 *
AnnaBridge 189:f392fc9709a3 4 * SPDX-License-Identifier: Apache-2.0
AnnaBridge 189:f392fc9709a3 5 *
AnnaBridge 189:f392fc9709a3 6 * Licensed under the Apache License, Version 2.0 (the "License");
AnnaBridge 189:f392fc9709a3 7 * you may not use this file except in compliance with the License.
AnnaBridge 189:f392fc9709a3 8 * You may obtain a copy of the License at
AnnaBridge 189:f392fc9709a3 9 *
AnnaBridge 189:f392fc9709a3 10 * http://www.apache.org/licenses/LICENSE-2.0
AnnaBridge 189:f392fc9709a3 11 *
AnnaBridge 189:f392fc9709a3 12 * Unless required by applicable law or agreed to in writing, software
AnnaBridge 189:f392fc9709a3 13 * distributed under the License is distributed on an "AS IS" BASIS,
AnnaBridge 189:f392fc9709a3 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
AnnaBridge 189:f392fc9709a3 15 * See the License for the specific language governing permissions and
AnnaBridge 189:f392fc9709a3 16 * limitations under the License.
AnnaBridge 189:f392fc9709a3 17 */
AnnaBridge 189:f392fc9709a3 18 #if DEVICE_RTC
AnnaBridge 189:f392fc9709a3 19
AnnaBridge 189:f392fc9709a3 20 #include "rtc_api.h"
AnnaBridge 189:f392fc9709a3 21
AnnaBridge 189:f392fc9709a3 22 static uint8_t rtc_init_flag = 0;
AnnaBridge 189:f392fc9709a3 23
AnnaBridge 189:f392fc9709a3 24 /** Initialize the RTC peripheral
AnnaBridge 189:f392fc9709a3 25 *
AnnaBridge 189:f392fc9709a3 26 * Powerup the RTC in perpetration for access. This function must be called
AnnaBridge 189:f392fc9709a3 27 * before any other RTC functions ares called. This does not change the state
AnnaBridge 189:f392fc9709a3 28 * of the RTC. It just enables access to it.
AnnaBridge 189:f392fc9709a3 29 *
AnnaBridge 189:f392fc9709a3 30 * @note This function is safe to call repeatedly - Tested by ::rtc_init_test
AnnaBridge 189:f392fc9709a3 31 */
AnnaBridge 189:f392fc9709a3 32 void rtc_init(void)
AnnaBridge 189:f392fc9709a3 33 {
AnnaBridge 189:f392fc9709a3 34 /* make sure RTC only init once */
AnnaBridge 189:f392fc9709a3 35 if (rtc_init_flag) {
AnnaBridge 189:f392fc9709a3 36 return;
AnnaBridge 189:f392fc9709a3 37 }
AnnaBridge 189:f392fc9709a3 38 rtc_init_flag = 1;
AnnaBridge 189:f392fc9709a3 39
AnnaBridge 189:f392fc9709a3 40 /* enable PMU and BKPI clocks */
AnnaBridge 189:f392fc9709a3 41 rcu_periph_clock_enable(RCU_BKPI);
AnnaBridge 189:f392fc9709a3 42 rcu_periph_clock_enable(RCU_PMU);
AnnaBridge 189:f392fc9709a3 43 /* allow access to BKP domain */
AnnaBridge 189:f392fc9709a3 44 pmu_backup_write_enable();
AnnaBridge 189:f392fc9709a3 45 /* enable LXTAL */
AnnaBridge 189:f392fc9709a3 46 rcu_osci_on(RCU_LXTAL);
AnnaBridge 189:f392fc9709a3 47 /* wait till LXTAL is ready */
AnnaBridge 189:f392fc9709a3 48 rcu_osci_stab_wait(RCU_LXTAL);
AnnaBridge 189:f392fc9709a3 49 /* select RCU_LXTAL as RTC clock source */
AnnaBridge 189:f392fc9709a3 50 rcu_rtc_clock_config(RCU_RTCSRC_LXTAL);
AnnaBridge 189:f392fc9709a3 51 /* enable RTC Clock */
AnnaBridge 189:f392fc9709a3 52 rcu_periph_clock_enable(RCU_RTC);
AnnaBridge 189:f392fc9709a3 53 /* wait for RTC registers synchronization */
AnnaBridge 189:f392fc9709a3 54 rtc_register_sync_wait();
AnnaBridge 189:f392fc9709a3 55 /* wait until last write operation on RTC registers has finished */
AnnaBridge 189:f392fc9709a3 56 rtc_lwoff_wait();
AnnaBridge 189:f392fc9709a3 57 /* set RTC prescaler: set RTC period to 1s */
AnnaBridge 189:f392fc9709a3 58 rtc_prescaler_set(32767);
AnnaBridge 189:f392fc9709a3 59 /* wait until last write operation on RTC registers has finished */
AnnaBridge 189:f392fc9709a3 60 rtc_lwoff_wait();
AnnaBridge 189:f392fc9709a3 61 }
AnnaBridge 189:f392fc9709a3 62
AnnaBridge 189:f392fc9709a3 63 /** Deinitialize RTC
AnnaBridge 189:f392fc9709a3 64 *
AnnaBridge 189:f392fc9709a3 65 * Powerdown the RTC in preparation for sleep, powerdown or reset. That should only
AnnaBridge 189:f392fc9709a3 66 * affect the CPU domain and not the time keeping logic.
AnnaBridge 189:f392fc9709a3 67 * After this function is called no other RTC functions should be called
AnnaBridge 189:f392fc9709a3 68 * except for ::rtc_init.
AnnaBridge 189:f392fc9709a3 69 */
AnnaBridge 189:f392fc9709a3 70 void rtc_free(void)
AnnaBridge 189:f392fc9709a3 71 {
AnnaBridge 189:f392fc9709a3 72 }
AnnaBridge 189:f392fc9709a3 73
AnnaBridge 189:f392fc9709a3 74 /** Check if the RTC has the time set and is counting
AnnaBridge 189:f392fc9709a3 75 *
AnnaBridge 189:f392fc9709a3 76 * @retval 0 The time reported by the RTC is not valid
AnnaBridge 189:f392fc9709a3 77 * @retval 1 The time has been set the RTC is counting
AnnaBridge 189:f392fc9709a3 78 */
AnnaBridge 189:f392fc9709a3 79 int rtc_isenabled(void)
AnnaBridge 189:f392fc9709a3 80 {
AnnaBridge 189:f392fc9709a3 81 if (RESET == (RTC_CTL & RTC_CTL_RSYNF)) {
AnnaBridge 189:f392fc9709a3 82 return 0;
AnnaBridge 189:f392fc9709a3 83 } else {
AnnaBridge 189:f392fc9709a3 84 return 1;
AnnaBridge 189:f392fc9709a3 85 }
AnnaBridge 189:f392fc9709a3 86 }
AnnaBridge 189:f392fc9709a3 87
AnnaBridge 189:f392fc9709a3 88 /** Get the current time from the RTC peripheral
AnnaBridge 189:f392fc9709a3 89 *
AnnaBridge 189:f392fc9709a3 90 * @return The current time in seconds
AnnaBridge 189:f392fc9709a3 91 *
AnnaBridge 189:f392fc9709a3 92 * @note Some RTCs are not synchronized with the main clock. If
AnnaBridge 189:f392fc9709a3 93 * this is the case with your RTC then you must read the RTC time
AnnaBridge 189:f392fc9709a3 94 * in a loop to prevent reading the wrong time due to a glitch.
AnnaBridge 189:f392fc9709a3 95 * The test ::rtc_glitch_test is intended to catch this bug.
AnnaBridge 189:f392fc9709a3 96 */
AnnaBridge 189:f392fc9709a3 97 time_t rtc_read(void)
AnnaBridge 189:f392fc9709a3 98 {
AnnaBridge 189:f392fc9709a3 99 return (rtc_counter_get());
AnnaBridge 189:f392fc9709a3 100 }
AnnaBridge 189:f392fc9709a3 101
AnnaBridge 189:f392fc9709a3 102 /** Write the current time in seconds to the RTC peripheral
AnnaBridge 189:f392fc9709a3 103 *
AnnaBridge 189:f392fc9709a3 104 * @param t The current time to be set in seconds.
AnnaBridge 189:f392fc9709a3 105 */
AnnaBridge 189:f392fc9709a3 106 void rtc_write(time_t t)
AnnaBridge 189:f392fc9709a3 107 {
AnnaBridge 189:f392fc9709a3 108 rtc_counter_set((uint32_t)t);
AnnaBridge 189:f392fc9709a3 109 rtc_lwoff_wait();
AnnaBridge 189:f392fc9709a3 110 }
AnnaBridge 189:f392fc9709a3 111
AnnaBridge 189:f392fc9709a3 112 #endif /* DEVICE_RTC */