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Merge pull request #11304 from aabadie/pr/stm32_common/rtc_improve

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stm32 common/rtc: reset the rtc when clock source has changed
This commit is contained in:
Vincent Dupont 2019-03-29 11:53:44 +01:00 committed by GitHub
commit 5e6205724d
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3 changed files with 23 additions and 0 deletions
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1
boards/b-l072z-lrwan1/include/periph_conf.h
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@ -31,6 +31,7 @@ extern "C" {
*/
#define CLOCK_HSI (16000000U) /* internal oscillator */
#define CLOCK_CORECLOCK (32000000U) /* desired core clock frequency */
#define CLOCK_LSE (1) /* enable low speed external oscillator */
/* configuration of PLL prescaler and multiply values */
/* CORECLOCK := HSI / CLOCK_PLL_DIV * CLOCK_PLL_MUL */

1
boards/nucleo-l073rz/include/periph_conf.h
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@ -35,6 +35,7 @@ extern "C" {
*/
#define CLOCK_HSI (16000000U) /* internal oscillator */
#define CLOCK_CORECLOCK (32000000U) /* desired core clock frequency */
#define CLOCK_LSE (1) /* enable low speed external oscillator */
/* configuration of PLL prescaler and multiply values */
/* CORECLOCK := HSI / CLOCK_PLL_DIV * CLOCK_PLL_MUL */

21
cpu/stm32_common/periph/rtc.c
View File

@ -138,6 +138,14 @@
* offset of 100 years. */
#define YEAR_OFFSET (100)
/* Use a magic number to determine the initial RTC source. This will be used
to know if a reset of the RTC is required at initialization. */
#if CLOCK_LSE
#define MAGIC_CLCK_NUMBER (0x1970)
#else
#define MAGIC_CLCK_NUMBER (0x1971)
#endif
static struct {
rtc_alarm_cb_t cb; /**< callback called from RTC interrupt */
void *arg; /**< argument passed to the callback */
@ -186,6 +194,19 @@ static inline void rtc_lock(void)
void rtc_init(void)
{
stmclk_dbp_unlock();
#if defined(CPU_FAM_STM32L0) || defined(CPU_FAM_STM32L1)
/* Compare the stored magic number with the current one. If it's different
it means the clock source has changed and thus a RTC reset is
required. */
if (RTC->BKP0R != MAGIC_CLCK_NUMBER) {
RCC->CSR |= RCC_CSR_RTCRST;
RCC->CSR &= ~RCC_CSR_RTCRST;
RTC->BKP0R = MAGIC_CLCK_NUMBER; /* Store the new magic number */
}
#endif
stmclk_dbp_lock();
/* enable low frequency clock */
stmclk_enable_lfclk();