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148 lines
3.5 KiB
148 lines
3.5 KiB
#include <libopencm3/stm32/pwr.h>
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#include <libopencm3/stm32/rcc.h>
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#include <libopencm3/stm32/rtc.h>
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#include <macros.h>
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#include <rtc.h>
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static void rtc_set_clock_source(enum rcc_osc clock_source)
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{
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uint32_t reg;
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switch (clock_source) {
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case RCC_LSE:
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/* Turn on the LSE and wait until it stabilised. */
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RCC_BDCR |= RCC_BDCR_LSEON;
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while ((reg = (RCC_BDCR & RCC_BDCR_LSERDY)) == 0);
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/* Choose LSE as the RTC clock source. */
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RCC_BDCR &= ~BITS(8, 9);
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RCC_BDCR |= BIT(8);
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break;
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case RCC_LSI:
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/* Turn on the LSI and wait until it stabilised. */
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RCC_CSR |= RCC_CSR_LSION;
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while ((reg = (RCC_CSR & RCC_CSR_LSIRDY)) == 0);
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/* Choose LSI as the RTC clock source. */
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RCC_BDCR &= ~BITS(8, 9);
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RCC_BDCR |= BIT(9);
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break;
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case RCC_HSE:
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/* Turn on the HSE and wait until it stabilised. */
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RCC_CR |= RCC_CR_HSEON;
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while ((reg = (RCC_CR & RCC_CR_HSERDY)) == 0);
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/* Choose HSE as the RTC clock source. */
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RCC_BDCR &= ~BITS(8, 9);
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RCC_BDCR |= BITS(8, 9);
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break;
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default:
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/* Unusable clock sources. Turn off the clock source for RTC. */
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RCC_BDCR &= ~BITS(8, 9);
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break;
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}
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}
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int rtc_get_time(struct tm *time)
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{
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uint32_t rtc_tr, rtc_dr;
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rtc_tr = RTC_TR;
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rtc_dr = RTC_DR;
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time->tm_sec = (unsigned char)(rtc_tr & 0xF);
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time->tm_sec += (unsigned char)(((rtc_tr >> 4) & 0xF) * 10);
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time->tm_min = (unsigned char)((rtc_tr >> 8) & 0xF);
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time->tm_min += (unsigned char)(((rtc_tr >> 12) & 0xF) * 10);
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time->tm_hour = (unsigned char)((rtc_tr >> 16) & 0xF);
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time->tm_hour += (unsigned char)(((rtc_tr >> 20) & 0xF) * 10);
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time->tm_mday = (unsigned char)(rtc_dr & 0xF);
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time->tm_mday += (unsigned char)(((rtc_dr >> 4) & 0x3) * 10);
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time->tm_mon = (unsigned char)((rtc_dr >> 8) & 0xF);
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time->tm_mon += (unsigned char)(((rtc_dr >> 12) & 0x1) * 10);
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time->tm_mon -= 1;
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time->tm_year = (unsigned char)((rtc_dr >> 16) & 0xF);
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time->tm_year += (unsigned char)(((rtc_dr >> 20) & 0xF) * 10);
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time->tm_year += 100;
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return 0;
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}
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static int rtc_set_time(struct tm *time)
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{
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uint32_t rtc_tr, rtc_dr;
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uint32_t mon, year;
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if (!time)
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return -1;
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mon = time->tm_mon + 1;
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year = time->tm_year - 100;
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rtc_tr = (time->tm_sec % 10);
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rtc_tr |= (time->tm_sec / 10) << 4;
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rtc_tr |= (time->tm_min % 10) << 8;
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rtc_tr |= (time->tm_min / 10) << 12;
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rtc_tr |= (time->tm_hour % 10) << 16;
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rtc_tr |= (time->tm_hour / 10) << 20;
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rtc_dr = (time->tm_mday % 10);
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rtc_dr |= (time->tm_mday / 10) << 4;
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rtc_dr |= (mon % 10) << 8;
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rtc_dr |= (mon / 10) << 12;
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rtc_dr |= (year % 10) << 16;
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rtc_dr |= (year / 10) << 20;
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RTC_TR = rtc_tr;
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RTC_DR = rtc_dr;
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return 0;
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}
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int rtc_init(struct tm *time)
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{
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/* Turn on power block to enable unlocking. */
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rcc_periph_clock_enable(RCC_PWR);
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pwr_disable_backup_domain_write_protect();
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/* Reset the RTC. */
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RCC_BDCR |= RCC_BDCR_BDRST;
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RCC_BDCR &= ~RCC_BDCR_BDRST;
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/* Enable the LSI and set it as the clock source for RTC. */
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rcc_osc_on(RCC_LSI);
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rcc_wait_for_osc_ready(RCC_LSI);
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rtc_set_clock_source(RCC_LSI);
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/* Enable the RTC clock */
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rcc_periph_clock_enable(RCC_RTC);
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/* Unlock the registers in the RTC domain. */
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rtc_unlock();
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/* Enter init mode. */
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RTC_ISR |= RTC_ISR_INIT;
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while ((RTC_ISR & RTC_ISR_INITF) == 0);
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/* Configure the RTC. */
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rtc_set_prescaler(0x1ff, 0x7f);
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rtc_set_time(time);
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/* Exit init mode. */
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RTC_ISR &= ~(RTC_ISR_INIT);
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/* Lock the registers. */
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rtc_lock();
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pwr_enable_backup_domain_write_protect();
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/* Wait for the synchronisation. */
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rtc_wait_for_synchro();
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return 0;
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}
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