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Optimize stm32 RTC accuracy

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lpxiao 2023-07-31 21:43:15 +08:00 committed by Mateusz Szafoni
parent 55a727b1ce
commit 3341a6d2a9
1 changed files with 36 additions and 33 deletions
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69
arch/arm/src/stm32/stm32_rtcounter.c
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@ -394,42 +394,45 @@ int up_rtc_initialize(void)
modifyreg32(STM32_RCC_BDCR, 0, RCC_BDCR_BDRST);
modifyreg32(STM32_RCC_BDCR, RCC_BDCR_BDRST, 0);
modifyreg16(STM32_RCC_BDCR, 0, RCC_BDCR_LSEON);
/* Wait for the LSE clock to be ready */
while ((getreg16(STM32_RCC_BDCR) & RCC_BDCR_LSERDY) == 0)
{
stm32_waste();
}
/* Select the lower power external 32,768Hz (Low-Speed External, LSE)
* oscillator as RTC Clock Source and enable the Clock.
*/
modifyreg16(STM32_RCC_BDCR, RCC_BDCR_RTCSEL_MASK, RCC_BDCR_RTCSEL_LSE);
/* Enable RTC and wait for RSF */
modifyreg16(STM32_RCC_BDCR, 0, RCC_BDCR_RTCEN);
stm32_rtc_waitlasttask();
stm32_rtc_wait4rsf();
stm32_rtc_waitlasttask();
/* Configure prescaler, note that these are write-only registers */
stm32_rtc_beginwr();
putreg16(STM32_RTC_PRESCALAR_VALUE >> 16, STM32_RTC_PRLH);
putreg16(STM32_RTC_PRESCALAR_VALUE & 0xffff, STM32_RTC_PRLL);
stm32_rtc_endwr();
stm32_rtc_wait4rsf();
stm32_rtc_waitlasttask();
/* Write the magic register after RTC initialization. */
putreg16(RTC_MAGIC, RTC_MAGIC_REG);
}
modifyreg16(STM32_RCC_BDCR, 0, RCC_BDCR_LSEON);
/* Wait for the LSE clock to be ready */
while ((getreg16(STM32_RCC_BDCR) & RCC_BDCR_LSERDY) == 0)
{
stm32_waste();
}
/* Select the lower power external 32,768Hz (Low-Speed External, LSE)
* oscillator as RTC Clock Source and enable the Clock.
*/
modifyreg16(STM32_RCC_BDCR, RCC_BDCR_RTCSEL_MASK, RCC_BDCR_RTCSEL_LSE);
/* Enable RTC and wait for RSF */
modifyreg16(STM32_RCC_BDCR, 0, RCC_BDCR_RTCEN);
stm32_rtc_waitlasttask();
stm32_rtc_wait4rsf();
stm32_rtc_waitlasttask();
/* Configure prescaler, note that these are write-only registers */
stm32_rtc_beginwr();
putreg16(STM32_RTC_PRESCALAR_VALUE >> 16, STM32_RTC_PRLH);
putreg16(STM32_RTC_PRESCALAR_VALUE & 0xffff, STM32_RTC_PRLL);
stm32_rtc_endwr();
stm32_rtc_wait4rsf();
stm32_rtc_waitlasttask();
#ifdef CONFIG_RTC_HIRES
/* Enable overflow interrupt - alarm interrupt is enabled in
* stm32_rtc_setalarm.