RTC精密数字校准

lindahnu

库函数HAL_RTCEx_SetSmoothCalib实现精密校准，假设RTC一天快了1秒，怎么理解使用这个函数呢？

eric2013

看了下这个函数，只有简单的寄存器设置，这个有必要研究下手册了

1. /**
   
2.   * @brief  Set the Smooth calibration parameters.
   
3.   * @param  hrtc RTC handle
   
4.   * @param  SmoothCalibPeriod Select the Smooth Calibration Period.
   
5.   *          This parameter can be can be one of the following values :
   
6.   *             @arg RTC_SMOOTHCALIB_PERIOD_32SEC: The smooth calibration period is 32s.
   
7.   *             @arg RTC_SMOOTHCALIB_PERIOD_16SEC: The smooth calibration period is 16s.
   
8.   *             @arg RTC_SMOOTHCALIB_PERIOD_8SEC: The smooth calibration period is 8s.
   
9.   * @param  SmoothCalibPlusPulses Select to Set or reset the CALP bit.
   
10.   *          This parameter can be one of the following values:
    
11.   *             @arg RTC_SMOOTHCALIB_PLUSPULSES_SET: Add one RTCCLK pulse every 2*11 pulses.
    
12.   *             @arg RTC_SMOOTHCALIB_PLUSPULSES_RESET: No RTCCLK pulses are added.
    
13.   * @param  SmoothCalibMinusPulsesValue Select the value of CALM[8:0] bits.
    
14.   *          This parameter can be one any value from 0 to 0x000001FF.
    
15.   * @note   To deactivate the smooth calibration, the field SmoothCalibPlusPulses
    
16.   *         must be equal to SMOOTHCALIB_PLUSPULSES_RESET and the field
    
17.   *         SmoothCalibMinusPulsesValue must be equal to 0.
    
18.   * @retval HAL status
    
19.   */
    
20. HAL_StatusTypeDef HAL_RTCEx_SetSmoothCalib(RTC_HandleTypeDef * hrtc, uint32_t SmoothCalibPeriod, uint32_t SmoothCalibPlusPulses, uint32_t SmoothCalibMinusPulsesValue)
    
21. {
    
22.   uint32_t tickstart;
    
23. 
    
24.   /* Check the parameters */
    
25.   assert_param(IS_RTC_SMOOTH_CALIB_PERIOD(SmoothCalibPeriod));
    
26.   assert_param(IS_RTC_SMOOTH_CALIB_PLUS(SmoothCalibPlusPulses));
    
27.   assert_param(IS_RTC_SMOOTH_CALIB_MINUS(SmoothCalibMinusPulsesValue));
    
28. 
    
29.   /* Process Locked */
    
30.   __HAL_LOCK(hrtc);
    
31. 
    
32.   hrtc->State = HAL_RTC_STATE_BUSY;
    
33. 
    
34.   /* Disable the write protection for RTC registers */
    
35.   __HAL_RTC_WRITEPROTECTION_DISABLE(hrtc);
    
36. 
    
37.   /* check if a calibration operation is pending */
    
38. #if defined(RTC_ICSR_RECALPF)
    
39.   if ((hrtc->Instance->ICSR & RTC_ICSR_RECALPF) != 0U)
    
40. #endif /* RTC_ICSR_RECALPF */
    
41. #if defined(RTC_ISR_RECALPF)
    
42.     if ((hrtc->Instance->ISR  & RTC_ISR_RECALPF)  != 0U)
    
43. #endif /* RTC_ISR_RECALPF */
    
44.     {
    
45.       tickstart = HAL_GetTick();
    
46. 
    
47.       /* Wait for pending calibration operation to finish */
    
48. #if defined(RTC_ICSR_RECALPF)
    
49.       while ((hrtc->Instance->ICSR & RTC_ICSR_RECALPF) != 0U)
    
50. #endif /* RTC_ICSR_RECALPF */
    
51. #if defined(RTC_ISR_RECALPF)
    
52.         while ((hrtc->Instance->ISR  & RTC_ISR_RECALPF)  != 0U)
    
53. #endif /* RTC_ISR_RECALPF */
    
54.         {
    
55.           if ((HAL_GetTick() - tickstart) > RTC_TIMEOUT_VALUE)
    
56.           {
    
57.             /* Enable the write protection for RTC registers */
    
58.             __HAL_RTC_WRITEPROTECTION_ENABLE(hrtc);
    
59. 
    
60.             /* Change RTC state */
    
61.             hrtc->State = HAL_RTC_STATE_TIMEOUT;
    
62. 
    
63.             /* Process Unlocked */
    
64.             __HAL_UNLOCK(hrtc);
    
65. 
    
66.             return HAL_TIMEOUT;
    
67.           }
    
68.         }
    
69.     }
    
70. 
    
71.   /* Configure the Smooth calibration settings */
    
72.   MODIFY_REG(hrtc->Instance->CALR, (RTC_CALR_CALP | RTC_CALR_CALW8 | RTC_CALR_CALW16 | RTC_CALR_CALM), (uint32_t)(SmoothCalibPeriod | SmoothCalibPlusPulses | SmoothCalibMinusPulsesValue));
    
73. 
    
74.   /* Enable the write protection for RTC registers */
    
75.   __HAL_RTC_WRITEPROTECTION_ENABLE(hrtc);
    
76. 
    
77.   /* Change RTC state */
    
78.   hrtc->State = HAL_RTC_STATE_READY;
    
79. 
    
80.   /* Process Unlocked */
    
81.   __HAL_UNLOCK(hrtc);
    
82. 
    
83.   return HAL_OK;
    
84. }
    

复制代码

eric2013

找到了，有个专门的软件包和相关文档。
https://www.st.com/en/embedded-software/x-cube-rtc.html

emwin

我们是有自己做高精度时钟仪，能到0.01秒/天

lindahnu

eric2013 发表于 2021-5-1 08:33
找到了，有个专门的软件包和相关文档。
https://www.st.com/en/embedded-software/x-cube-rtc.html

仍然一头雾水，想要那种傻瓜式的，谢谢分享