1.LPTIM介绍
STM32L0系列有个LPTIM定时器，即lowpowertimer,低功耗定时器

( D  x5 {, F" n/ b4 v' G4 F# e5 O可以看到可供LPTIM使用时钟源分为如下：
/ g' _+ j8 I2 ^4 ?内部时钟源：LSE，LSI，HSI或APB时钟
/ ~: T+ N$ J/ b( ^2 E1 W外部时钟源：LPTIM输入的外部时钟源
/ j" z6 N: n; ], M# r6 y9 Qps：如果以LSE，LSI或外部时钟为时钟源时，能够从停止模式唤醒设备。
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8 M" Y1 _( m8 p0 O5 p+ K. V本文记录使用LSI为时钟源使用LPTIM

! [" |9 F9 b2 {2.配置时钟源并且启动

1. /**
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2.   * @brief System Clock Configuration
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3.   * @retval None
   
4.   */
   
5. void SystemClock_Config(void)
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6. {
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7.   RCC_OscInitTypeDef RCC_OscInitStruct = {0};
   
8.   RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
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9.   RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
   
10. 
    
11.   /** Configure the main internal regulator output voltage
    
12.   */
    
13.   __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
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14.   /** Initializes the CPU, AHB and APB busses clocks
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15.   */
    
16.   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI|RCC_OSCILLATORTYPE_MSI;
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17.   RCC_OscInitStruct.LSIState = RCC_LSI_ON;
    
18.   RCC_OscInitStruct.MSIState = RCC_MSI_ON;
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19.   RCC_OscInitStruct.MSICalibrationValue = 0;
    
20.   RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_6;
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21.   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
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22.   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
    
23.   {
    
24.     Error_Handler();
    
25.   }
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26.   /** Initializes the CPU, AHB and APB busses clocks
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27.   */
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28.   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
    
29.                               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
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30.   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
    
31.   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
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32.   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
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33.   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
    
34. 
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35.   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
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36.   {
    
37.     Error_Handler();
    
38.   }
    
39. 
    
40.     PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_RTC|RCC_PERIPHCLK_LPTIM1;
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41.     PeriphClkInit.RTCClockSelection = RCC_RTCCLKSOURCE_LSI;
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42.     PeriphClkInit.LptimClockSelection = RCC_LPTIM1CLKSOURCE_LSI;
    
43. 
    
44.     if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
    
45.     {
    
46.     Error_Handler();
    
47.     }
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48. }

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1 N7 _. Y! G- o以上是完整的时钟配置函数，使用LPTIM最主要的配置由如下构成：

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1. RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI;
   
2. RCC_OscInitStruct.LSIState = RCC_LSI_ON;
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3. HAL_RCC_OscConfig(&RCC_OscInitStruct);
   
4. 
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5. PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPTIM1;
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6. PeriphClkInit.LptimClockSelection = RCC_LPTIM1CLKSOURCE_LSI;
   
7. HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);

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, h, `: ]+ H- M4 G1 k+ L: I3.初始化配置LPTIM

1. /**
   
2.   * @brief LPTIM1 Initialization Function
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3.   * @param None
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4.   * @retval None
   
5.   */
   
6. void MX_LPTIM1_Init(void)  //0.037Mhz  (1+period / 0.037(37000)) = 1s period=36999
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7. {
   
8.   hlptim1.Instance = LPTIM1;
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9.   hlptim1.Init.Clock.Source = LPTIM_CLOCKSOURCE_APBCLOCK_LPOSC;
   
10.   hlptim1.Init.Clock.Prescaler = LPTIM_PRESCALER_DIV1;
    
11.   hlptim1.Init.Trigger.Source = LPTIM_TRIGSOURCE_SOFTWARE;
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12.   hlptim1.Init.OutputPolarity = LPTIM_OUTPUTPOLARITY_HIGH;
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13.   hlptim1.Init.UpdateMode = LPTIM_UPDATE_IMMEDIATE;
    
14.   hlptim1.Init.CounterSource = LPTIM_COUNTERSOURCE_INTERNAL;
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15.   if (HAL_LPTIM_Init(&hlptim1) != HAL_OK)
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16.   {
    
17.     Error_Handler();
    
18.   }
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19. }

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4.LPTIM中断处理函数
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1. void LPTIM1_IRQHandler(void)
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2. {
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3.   HAL_LPTIM_IRQHandler(&hlptim1);
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4. }

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0 m, A: G. x" i) x2 N$ h! x5.启用LPTIM，中断触发回调函数
启用LPTIM分为多种方式：如脉冲，PWM，计数等。
* Q8 k9 ^  L9 [8 ^; B: j" a具体可参考HAL_LPTIM_IRQHandler函数的实现。
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1. /**
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2.   * @brief  Handle LPTIM interrupt request.
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3.   * @param  hlptim LPTIM handle
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4.   * @retval None
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5.   */
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6. void HAL_LPTIM_IRQHandler(LPTIM_HandleTypeDef *hlptim)
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7. {
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8.   /* Compare match interrupt */
   
9.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_CMPM) != RESET)
   
10.   {
    
11.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_CMPM) != RESET)
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12.     {
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13.       /* Clear Compare match flag */
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14.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_CMPM);
    
15. 
    
16.       /* Compare match Callback */
    
17. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
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18.       hlptim->CompareMatchCallback(hlptim);
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19. #else
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20.       HAL_LPTIM_CompareMatchCallback(hlptim);
    
21. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
    
22.     }
    
23.   }
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24. 
    
25.   /* Autoreload match interrupt */
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26.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_ARRM) != RESET)
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27.   {
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28.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_ARRM) != RESET)
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29.     {
    
30.       /* Clear Autoreload match flag */
    
31.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_ARRM);
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32. 
    
33.       /* Autoreload match Callback */
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34. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
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35.       hlptim->AutoReloadMatchCallback(hlptim);
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36. #else
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37.       HAL_LPTIM_AutoReloadMatchCallback(hlptim);
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38. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
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39.     }
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40.   }
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41. 
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42.   /* Trigger detected interrupt */
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43.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_EXTTRIG) != RESET)
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44.   {
    
45.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_EXTTRIG) != RESET)
    
46.     {
    
47.       /* Clear Trigger detected flag */
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48.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_EXTTRIG);
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49. 
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50.       /* Trigger detected callback */
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51. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
    
52.       hlptim->TriggerCallback(hlptim);
    
53. #else
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54.       HAL_LPTIM_TriggerCallback(hlptim);
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55. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
    
56.     }
    
57.   }
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58. 
    
59.   /* Compare write interrupt */
    
60.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_CMPOK) != RESET)
    
61.   {
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62.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_CMPOK) != RESET)
    
63.     {
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64.       /* Clear Compare write flag */
    
65.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_CMPOK);
    
66. 
    
67.       /* Compare write Callback */
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68. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
    
69.       hlptim->CompareWriteCallback(hlptim);
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70. #else
    
71.       HAL_LPTIM_CompareWriteCallback(hlptim);
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72. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
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73.     }
    
74.   }
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75. 
    
76.   /* Autoreload write interrupt */
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77.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_ARROK) != RESET)
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78.   {
    
79.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_ARROK) != RESET)
    
80.     {
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81.       /* Clear Autoreload write flag */
    
82.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_ARROK);
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83. 
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84.       /* Autoreload write Callback */
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85. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
    
86.       hlptim->AutoReloadWriteCallback(hlptim);
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87. #else
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88.       HAL_LPTIM_AutoReloadWriteCallback(hlptim);
    
89. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
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90.     }
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91.   }
    
92. 
    
93.   /* Direction counter changed from Down to Up interrupt */
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94.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_UP) != RESET)
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95.   {
    
96.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_UP) != RESET)
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97.     {
    
98.       /* Clear Direction counter changed from Down to Up flag */
    
99.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_UP);
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100. 
     
101.       /* Direction counter changed from Down to Up Callback */
     
102. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
     
103.       hlptim->DirectionUpCallback(hlptim);
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104. #else
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105.       HAL_LPTIM_DirectionUpCallback(hlptim);
     
106. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
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107.     }
     
108.   }
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109. 
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110.   /* Direction counter changed from Up to Down interrupt */
     
111.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_DOWN) != RESET)
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112.   {
     
113.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_DOWN) != RESET)
     
114.     {
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115.       /* Clear Direction counter changed from Up to Down flag */
     
116.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_DOWN);
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117. 
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118.       /* Direction counter changed from Up to Down Callback */
     
119. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
     
120.       hlptim->DirectionDownCallback(hlptim);
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121. #else
     
122.       HAL_LPTIM_DirectionDownCallback(hlptim);
     
123. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
     
124.     }
     
125.   }
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126. }

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这里示例TimeOut的方式回调。
* P! ]" G; p0 @开启LPTIM定时器需要调用 HAL_LPTIM_TimeOut_Start_IT
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1. //HAL_LPTIM_TimeOut_Start_IT  <=> HAL_LPTIM_CompareMatchCallback
   
2. void HAL_LPTIM_CompareMatchCallback(LPTIM_HandleTypeDef *hlptim)
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3. {
   
4.     HAL_GPIO_TogglePin(GPIOB,GPIO_PIN_8);
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5. }

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6.main.c 主函数
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1. int main(void)
   
2. {
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3.     HAL_Init();
   
4.     /* Configure the system clock */
   
5.     SystemClock_Config();
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6. 
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7.     MX_LPTIM1_Init();
   
8.     //(1+period / 0.037(37000)) = 1s period=36999  1s触发一次
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9.     HAL_LPTIM_TimeOut_Start_IT(&hlptim1,36999,1000);
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10.     while(1){
    
11.         HAL_Delay(1000);
    
12.     }
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