Posted on November 10, 2017 at 21:03Hi,
I need to calibrate my RTC crystal that is drifting about 7 seconds every 18014 that according to my calculations is about 389 ppm. I Tryed to perform the calibration with the following initialization code, but regardless of the HAL_RTCEx_SetSmoothCalib function, the drift is the same. Is there any special procedure to proper perform the calibration?
static void rtc_config(void)
{
hrtc.Instance = RTC;
if(hrtc.Instance->ISR & RTC_ISR_INITS)
{
hrtc.Init.HourFormat = RTC_HOURFORMAT_24;
hrtc.Init.AsynchPrediv = 127;
hrtc.Init.SynchPrediv = 255;
hrtc.Init.OutPut = RTC_OUTPUT_DISABLE;
hrtc.Init.OutPutRemap = RTC_OUTPUT_REMAP_NONE;
hrtc.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
hrtc.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
if (HAL_RTC_Init(&hrtc) != HAL_OK)
{
Error_Handler();
}
/* Get the RTC current Time */
rtc_get_real_time();
if (HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, 2048, RTC_WAKEUPCLOCK_RTCCLK_DIV16) != HAL_OK)
{
//Error_Handler();
}
}
else
{
MX_RTC_Init();
/* Get the RTC current Time */
rtc_set_time(946684800);
}
while(hrtc.Instance->ISR & RTC_ISR_INITF);
HAL_RTCEx_SetSmoothCalib(&hrtc, RTC_SMOOTHCALIB_PERIOD_32SEC, RTC_SMOOTHCALIB_PLUSPULSES_SET, 133);
}
Thank you for the help;
