mirror of https://github.com/ARMmbed/mbed-os.git
83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2006-2015 ARM Limited
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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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#include "rtc_api.h"
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static void init(void) {
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// enable PORTC clock
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SIM->SCGC5 |= SIM_SCGC5_PORTC_MASK;
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// enable RTC clock
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SIM->SCGC6 |= SIM_SCGC6_RTC_MASK;
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// OSC32 as source
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SIM->SOPT1 &= ~SIM_SOPT1_OSC32KSEL_MASK;
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SIM->SOPT1 |= SIM_SOPT1_OSC32KSEL(0);
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}
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void rtc_init(void) {
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init();
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// Enable the oscillator
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// Teensy3.1 requires 20pF MCU loading capacitors for 32KHz RTC oscillator
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/* RTC->CR: SC2P=0,SC4P=1,SC8P=0,SC16P=1,CLKO=0,OSCE=1,UM=0,SUP=0,SPE=0,SWR=0 */
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RTC->CR |= RTC_CR_OSCE_MASK |RTC_CR_SC16P_MASK | RTC_CR_SC4P_MASK;
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//Configure the TSR. default value: 1
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RTC->TSR = 1;
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// enable counter
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RTC->SR |= RTC_SR_TCE_MASK;
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}
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void rtc_free(void) {
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// [TODO]
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}
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/*
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* Little check routine to see if the RTC has been enabled
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* 0 = Disabled, 1 = Enabled
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*/
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int rtc_isenabled(void) {
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// even if the RTC module is enabled,
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// as we use RTC_CLKIN and an external clock,
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// we need to reconfigure the pins. That is why we
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// call init() if the rtc is enabled
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// if RTC not enabled return 0
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SIM->SCGC5 |= SIM_SCGC5_PORTC_MASK;
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SIM->SCGC6 |= SIM_SCGC6_RTC_MASK;
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if ((RTC->SR & RTC_SR_TCE_MASK) == 0)
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return 0;
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init();
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return 1;
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}
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time_t rtc_read(void) {
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return RTC->TSR;
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}
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void rtc_write(time_t t) {
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// disable counter
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RTC->SR &= ~RTC_SR_TCE_MASK;
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// write seconds
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RTC->TSR = t;
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// re-enable counter
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RTC->SR |= RTC_SR_TCE_MASK;
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}
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