1.LPTIM介绍
& i1 Q% L/ J! _0 P0 \. q: t" \STM32L0系列有个LPTIM定时器，即lowpowertimer,低功耗定时器

可以看到可供LPTIM使用时钟源分为如下：
% U0 ^3 e  }. g7 m内部时钟源：LSE，LSI，HSI或APB时钟
6 n/ c+ T( x1 W5 X2 w外部时钟源：LPTIM输入的外部时钟源
2 b8 ^6 b: s( D% H5 V8 S; M$ @ps：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。

本文记录使用LSI为时钟源使用LPTIM

( f* z1 d- K/ I: I- I4 B3 L! W* E7 h$ Z2.配置时钟源并且启动

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

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( T, B: x/ h9 W" \1 V+ S/ I/ j& l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;
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2. RCC_OscInitStruct.LSIState = RCC_LSI_ON;
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3. HAL_RCC_OscConfig(&RCC_OscInitStruct);
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4. 
   
5. PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPTIM1;
   
6. PeriphClkInit.LptimClockSelection = RCC_LPTIM1CLKSOURCE_LSI;
   
7. HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);

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3.初始化配置LPTIM
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1. /**
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2.   * @brief LPTIM1 Initialization Function
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3.   * @param None
   
4.   * @retval None
   
5.   */
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6. void MX_LPTIM1_Init(void)  //0.037Mhz  (1+period / 0.037(37000)) = 1s period=36999
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7. {
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8.   hlptim1.Instance = LPTIM1;
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9.   hlptim1.Init.Clock.Source = LPTIM_CLOCKSOURCE_APBCLOCK_LPOSC;
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10.   hlptim1.Init.Clock.Prescaler = LPTIM_PRESCALER_DIV1;
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11.   hlptim1.Init.Trigger.Source = LPTIM_TRIGSOURCE_SOFTWARE;
    
12.   hlptim1.Init.OutputPolarity = LPTIM_OUTPUTPOLARITY_HIGH;
    
13.   hlptim1.Init.UpdateMode = LPTIM_UPDATE_IMMEDIATE;
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14.   hlptim1.Init.CounterSource = LPTIM_COUNTERSOURCE_INTERNAL;
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15.   if (HAL_LPTIM_Init(&hlptim1) != HAL_OK)
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16.   {
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17.     Error_Handler();
    
18.   }
    
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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5.启用LPTIM，中断触发回调函数
8 P& G% g5 ~" U* }7 l) }启用LPTIM分为多种方式：如脉冲，PWM，计数等。
具体可参考HAL_LPTIM_IRQHandler函数的实现。

1. /**
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2.   * @brief  Handle LPTIM interrupt request.
   
3.   * @param  hlptim LPTIM handle
   
4.   * @retval None
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5.   */
   
6. void HAL_LPTIM_IRQHandler(LPTIM_HandleTypeDef *hlptim)
   
7. {
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8.   /* Compare match interrupt */
   
9.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_CMPM) != RESET)
   
10.   {
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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);
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15. 
    
16.       /* Compare match Callback */
    
17. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
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18.       hlptim->CompareMatchCallback(hlptim);
    
19. #else
    
20.       HAL_LPTIM_CompareMatchCallback(hlptim);
    
21. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
    
22.     }
    
23.   }
    
24. 
    
25.   /* Autoreload match interrupt */
    
26.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_ARRM) != RESET)
    
27.   {
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28.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_ARRM) != RESET)
    
29.     {
    
30.       /* Clear Autoreload match flag */
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31.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_ARRM);
    
32. 
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33.       /* Autoreload match Callback */
    
34. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
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35.       hlptim->AutoReloadMatchCallback(hlptim);
    
36. #else
    
37.       HAL_LPTIM_AutoReloadMatchCallback(hlptim);
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38. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
    
39.     }
    
40.   }
    
41. 
    
42.   /* Trigger detected interrupt */
    
43.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_EXTTRIG) != RESET)
    
44.   {
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45.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_EXTTRIG) != RESET)
    
46.     {
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47.       /* Clear Trigger detected flag */
    
48.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_EXTTRIG);
    
49. 
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50.       /* Trigger detected callback */
    
51. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
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52.       hlptim->TriggerCallback(hlptim);
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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)
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63.     {
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64.       /* Clear Compare write flag */
    
65.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_CMPOK);
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66. 
    
67.       /* Compare write Callback */
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68. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
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69.       hlptim->CompareWriteCallback(hlptim);
    
70. #else
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71.       HAL_LPTIM_CompareWriteCallback(hlptim);
    
72. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
    
73.     }
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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. 
    
84.       /* Autoreload write Callback */
    
85. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
    
86.       hlptim->AutoReloadWriteCallback(hlptim);
    
87. #else
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88.       HAL_LPTIM_AutoReloadWriteCallback(hlptim);
    
89. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
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90.     }
    
91.   }
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92. 
    
93.   /* Direction counter changed from Down to Up interrupt */
    
94.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_UP) != RESET)
    
95.   {
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96.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_UP) != RESET)
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97.     {
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98.       /* Clear Direction counter changed from Down to Up flag */
    
99.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_UP);
    
100. 
     
101.       /* Direction counter changed from Down to Up Callback */
     
102. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
     
103.       hlptim->DirectionUpCallback(hlptim);
     
104. #else
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105.       HAL_LPTIM_DirectionUpCallback(hlptim);
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106. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
     
107.     }
     
108.   }
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109. 
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110.   /* Direction counter changed from Up to Down interrupt */
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111.   if (__HAL_LPTIM_GET_FLAG(hlptim, LPTIM_FLAG_DOWN) != RESET)
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112.   {
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113.     if (__HAL_LPTIM_GET_IT_SOURCE(hlptim, LPTIM_IT_DOWN) != RESET)
     
114.     {
     
115.       /* Clear Direction counter changed from Up to Down flag */
     
116.       __HAL_LPTIM_CLEAR_FLAG(hlptim, LPTIM_FLAG_DOWN);
     
117. 
     
118.       /* Direction counter changed from Up to Down Callback */
     
119. #if (USE_HAL_LPTIM_REGISTER_CALLBACKS == 1)
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120.       hlptim->DirectionDownCallback(hlptim);
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121. #else
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122.       HAL_LPTIM_DirectionDownCallback(hlptim);
     
123. #endif /* USE_HAL_LPTIM_REGISTER_CALLBACKS */
     
124.     }
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125.   }
     
126. }

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* M6 \1 y5 m0 k1 F  c  k& o& L这里示例TimeOut的方式回调。
$ g! L/ D$ W. W( Q  o: c9 p+ V1 F, u3 L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)
   
3. {
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4.     HAL_GPIO_TogglePin(GPIOB,GPIO_PIN_8);
   
5. }

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' C7 c" h- Y& A0 l6.main.c 主函数

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);
   
10.     while(1){
    
11.         HAL_Delay(1000);
    
12.     }
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