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notronotro
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atmel-samd: RTC: Improve precision when setting datetime
The prescaler is not reset when setting the counter so we can be off by as much as 1023/1024 seconds. Fix this by resetting the RTC module.
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  • ports/atmel-samd/common-hal/rtc

‎ports/atmel-samd/common-hal/rtc/RTC.c‎

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -64,6 +64,12 @@ void common_hal_rtc_get_time(timeutils_struct_time_t *tm) {
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}
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void common_hal_rtc_set_time(timeutils_struct_time_t *tm) {
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// Reset prescaler to increase initial precision. Otherwise we can be up to 1 second off already.
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uint32_t freqcorr = hri_rtcmode0_read_FREQCORR_reg(calendar.device.hw);
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calendar_deinit(&calendar);
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rtc_init();
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hri_rtcmode0_write_FREQCORR_reg(calendar.device.hw, freqcorr);
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struct calendar_date date = {
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.year = tm->tm_year,
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.month = tm->tm_mon,

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