mirror of
https://github.com/eddyem/stm32samples.git
synced 2025-12-06 02:35:23 +03:00
134 lines
4.4 KiB
C
134 lines
4.4 KiB
C
/*
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* This file is part of the rtc project.
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* Copyright 2023 Edward V. Emelianov <edward.emelianoff@gmail.com>.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stm32g0.h>
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#include "rtc.h"
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#ifndef WAITWHILE
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#define WAITWHILE(x) do{register uint32_t StartUpCounter = 0; while((x) && (++StartUpCounter < 0xffffff)){nop();}}while(0)
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#endif
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static const uint8_t maxdays[12] = {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
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// i - in, r - rest of divide
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#if 0
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static uint16_t div10s(uint16_t i, uint16_t *r){ // divide by 10
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uint32_t u = i;
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u *= 52429;
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u >>= 19;
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if(r) *r = i - 10*u;
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return (uint16_t)u;
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}
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#endif
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static uint8_t div10b(uint8_t i, uint8_t *r){ // divide by 10
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uint32_t u = i;
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u *= 52429;
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u >>= 19;
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if(r) *r = i - 10*u;
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return (uint8_t)u;
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}
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static uint8_t DEC2BCD(uint8_t x){
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uint8_t d, r;
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d = div10b(x, &r);
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return (d << 4 | r);
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}
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int rtc_setdate(rtc_t *d){
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if(d->year > 99) return FALSE;
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if(d->month > 12 || d->month == 0) return FALSE;
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if(d->day > maxdays[d->month - 1] || d->day == 0) return FALSE;
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if(d->month == 2 && d->day == 29 && (d->year & 4) != 4) return FALSE; // not leap year
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if(d->weekday > 7 || d->weekday == 0) return FALSE;
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RTC->ICSR |= RTC_ICSR_INIT;
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WAITWHILE(!(RTC->ICSR & RTC_ICSR_INITF));
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RTC->DR = DEC2BCD(d->year) << RTC_DR_YU_Pos | d->weekday << RTC_DR_WDU_Pos | DEC2BCD(d->month) << RTC_DR_MU_Pos | DEC2BCD(d->day) << RTC_DR_DU_Pos;
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RTC->ICSR &= ~RTC_ICSR_INIT;
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return TRUE;
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}
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int rtc_settime(rtc_t *t){
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if(t->hour > 23) return FALSE;
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if(t->minute > 59) return FALSE;
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if(t->second > 59) return FALSE;
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RTC->ICSR |= RTC_ICSR_INIT;
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WAITWHILE(!(RTC->ICSR & RTC_ICSR_INITF));
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RTC->TR = DEC2BCD(t->hour) << RTC_TR_HU_Pos | DEC2BCD(t->minute) << RTC_TR_MNU_Pos | DEC2BCD(t->second) << RTC_TR_SU_Pos;
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RTC->ICSR &= ~RTC_ICSR_INIT;
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return TRUE;
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}
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void rtc_setup(){
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PWR->CR1 |= PWR_CR1_DBP; // disable RTC write protection
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// turn on LSE and switch RTC to it
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RCC->APBENR1 |= RCC_APBENR1_RTCAPBEN;
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RCC->BDCR = RCC_BDCR_LSEON;
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WAITWHILE(!(RCC->BDCR & RCC_BDCR_LSERDY));
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RCC->BDCR |= RCC_BDCR_RTCEN | RCC_BDCR_RTCSEL_0;
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// unlock RCC
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RTC->WPR = 0xCA;
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RTC->WPR = 0x53;
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RTC->ICSR |= RTC_ICSR_INIT;
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WAITWHILE(!(RTC->ICSR & RTC_ICSR_INITF));
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RTC->PRER = (0x7f << RTC_PRER_PREDIV_A_Pos) | 0xff; // prediv_a = 127, prediv_s = 255
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// here we can init starting time: monday of 1 jan 2001, 00:00:00
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// RTC->DR = 1 << RTC_DR_YU_Pos | 1 << RTC_DR_WDU_Pos | 1 << RTC_DR_MU_Pos | 1 << RTC_DR_DU_Pos;
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// RTC->TR = 0;
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// RTC->CR is default - 0
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// now turn off INIT bit, RTC will go on
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RTC->ICSR &= ~RTC_ICSR_INIT;
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}
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void get_curtime(rtc_t *t){
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WAITWHILE(!(RTC->ICSR & RTC_ICSR_RSF));
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register uint32_t r = RTC->TR;
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#define BCDu(shift) ((r >> shift) & 0xf)
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t->second = BCDu(RTC_TR_SU_Pos) + 10 * BCDu(RTC_TR_ST_Pos);
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t->minute = BCDu(RTC_TR_MNU_Pos) + 10 * BCDu(RTC_TR_MNT_Pos);
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t->hour = BCDu(RTC_TR_HU_Pos) + 10 * BCDu(RTC_TR_HT_Pos);
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r = RTC->DR;
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t->day = BCDu(RTC_DR_DU_Pos) + 10 * BCDu(RTC_DR_DT_Pos);
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t->month = BCDu(RTC_DR_MU_Pos);
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if(r & RTC_DR_MT) t->month += 10;
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t->weekday = (r >> RTC_DR_WDU_Pos) & 0x7;
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t->year = BCDu(RTC_DR_YU_Pos) + 10 * BCDu(RTC_DR_YT_Pos);
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}
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// set calibration value
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int rtc_setcalib(int calval){
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if(calval < -511 || calval > 512) return FALSE;
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uint32_t calp = 0, calm = 0;
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if(calval < 0) calm = -calval;
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else if(calval > 0){
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calp = RTC_CALR_CALP;
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calm = 512 - calval;
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}
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// unlock RCC
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RTC->WPR = 0xCA;
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RTC->WPR = 0x53;
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RTC->CALR = calp | calm;
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return 1;
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}
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int rtc_getcalib(){
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int calval = (RTC->CALR & RTC_CALR_CALP) ? 512 : 0;
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calval -= RTC->CALR & 0x1ff;
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return calval;
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}
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