STM32H7的低功耗定时器LPTIM，实现芯片进入停机状态后做PWM输出

eric2013

说明：

测试的官方例子：LPTIM_PWM_LSE。

使用LPTIM的好处是系统处于睡眠，停机状态可以正常工作（除了待机模式）。

这个例子选择了LSE作为LPTIM1的时钟源，输出一个占空比50%，频率327.68KHz的波形。

并且设了一个用户按键唤醒停机模式，唤醒后停止PWM输出。


波形输出：




测试代码：

此功能重点还是函数HAL_LPTIM_Init的参数配置学习。

1. /* Private typedef -----------------------------------------------------------*/
   
2. /* Private define ------------------------------------------------------------*/
   
3. /* Set the Maximum value of the counter (Auto-Reload) that defines the Period */
   
4. #define PeriodValue             (uint32_t) (100 - 1)
   
5. 
   
6. /* Set the Compare value that defines the duty cycle */
   
7. #define PulseValue              (uint32_t) (50 - 1)
   
8. 
   
9. /* Private macro -------------------------------------------------------------*/
   
10. /* Private variables ---------------------------------------------------------*/
    
11. /* LPTIM handle declaration */
    
12. LPTIM_HandleTypeDef             LptimHandle;
    
13. 
    
14. /* Clocks structure declaration */
    
15. RCC_PeriphCLKInitTypeDef        RCC_PeriphCLKInitStruct;
    
16. 
    
17. /* Private function prototypes -----------------------------------------------*/
    
18. static void SystemClock_Config(void);
    
19. static HAL_StatusTypeDef LSE_ClockEnable(void);
    
20. static void Error_Handler(void);
    
21. static void CPU_CACHE_Enable(void);
    
22. /* Private functions ---------------------------------------------------------*/
    
23. 
    
24. /**
    
25.   * @brief  Main program
    
26.   * @param  None
    
27.   * @retval None
    
28.   */
    
29. int main(void)
    
30. {
    
31.   /* Enable the CPU Cache */
    
32.   CPU_CACHE_Enable();
    
33.   
    
34.   /* STM32H7xx HAL library initialization:
    
35.        - Systick timer is configured by default as source of time base, but user
    
36.          can eventually implement his proper time base source (a general purpose
    
37.          timer for example or other time source), keeping in mind that Time base
    
38.          duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and
    
39.          handled in milliseconds basis.
    
40.        - Set NVIC Group Priority to 4
    
41.        - Low Level Initialization
    
42.      */
    
43.   HAL_Init();
    
44. 
    
45.   /* Configure the system clock to 400 MHz */
    
46.   SystemClock_Config();
    
47. 
    
48.   /* Configure LED2 */
    
49.   BSP_LED_Init(LED2);
    
50.   
    
51.   /* User push-button (EXTI_Line15_10) will be used to wakeup the system from Stop mode */
    
52.   BSP_PB_Init(BUTTON_USER, BUTTON_MODE_EXTI);
    
53. 
    
54.   /* Enable the LSE Clock */
    
55.   if (LSE_ClockEnable() != HAL_OK)
    
56.   {
    
57.     Error_Handler();
    
58.   }
    
59.   
    
60.   /* ### - 1 - Re-target the LSE to Clock the LPTIM Counter ################# */
    
61.   /* Select the LSE clock as LPTIM peripheral clock */
    
62.   RCC_PeriphCLKInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPTIM1;
    
63.   RCC_PeriphCLKInitStruct.Lptim1ClockSelection = RCC_LPTIM1CLKSOURCE_LSE;  
    
64.   HAL_RCCEx_PeriphCLKConfig(&RCC_PeriphCLKInitStruct);
    
65.   
    
66.   
    
67.   /* ### - 2 - Initialize the LPTIM peripheral ############################## */
    
68.   /*
    
69.    *  Instance        = LPTIM1
    
70.    *  Clock Source    = APB or LowPowerOSCillator (in this example LSE is
    
71.    *                    already selected from the RCC stage)
    
72.    *  Counter source  = External event.
    
73.    *  Clock prescaler = 1 (No division)
    
74.    *  Counter Trigger = Software trigger
    
75.    *  Output Polarity = High
    
76.    *  Update mode     = Immediate (Registers are immediately updated after any
    
77.    *                    write access)
    
78.    */
    
79. 
    
80.   LptimHandle.Instance = LPTIM1;
    
81.   
    
82.   LptimHandle.Init.Clock.Source    = LPTIM_CLOCKSOURCE_APBCLOCK_LPOSC;
    
83.   LptimHandle.Init.Clock.Prescaler = LPTIM_PRESCALER_DIV1;  
    
84.   LptimHandle.Init.CounterSource   = LPTIM_COUNTERSOURCE_INTERNAL;
    
85.   LptimHandle.Init.Trigger.Source  = LPTIM_TRIGSOURCE_SOFTWARE;
    
86.   LptimHandle.Init.OutputPolarity  = LPTIM_OUTPUTPOLARITY_HIGH;
    
87.   LptimHandle.Init.UpdateMode      = LPTIM_UPDATE_IMMEDIATE;
    
88.   LptimHandle.Init.Input1Source    = LPTIM_INPUT1SOURCE_GPIO;
    
89.   LptimHandle.Init.Input2Source    = LPTIM_INPUT2SOURCE_GPIO;
    
90.   
    
91.   /* Initialize LPTIM peripheral according to the passed parameters */
    
92.   if (HAL_LPTIM_Init(&LptimHandle) != HAL_OK)
    
93.   {
    
94.     Error_Handler();
    
95.   }
    
96. 
    
97.   /* ### - 3 - Start counting in interrupt mode ############################# */
    
98.   /*
    
99.    *  Period = 99
    
100.    *  Pulse  = 49
     
101.    *  According to this configuration, the duty cycle will be equal to 50%
     
102.    */
     
103.   if (HAL_LPTIM_PWM_Start(&LptimHandle, PeriodValue, PulseValue) != HAL_OK)
     
104.   {
     
105.     Error_Handler();
     
106.   }
     
107.   
     
108.   /* ### - 4 - Enter in Stop mode ########################################### */
     
109.   HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);
     
110.   
     
111.   /* ### - 5 - Stop counting when leaving Stop mode ########################## */
     
112.   if (HAL_LPTIM_PWM_Stop(&LptimHandle) != HAL_OK)
     
113.   {
     
114.     Error_Handler();
     
115.   }
     
116. 
     
117.   /* Infinite Loop */
     
118.   while (1)
     
119.   {        
     
120.   }
     
121. }
     
122. 
     
123. /**
     
124.   * @brief  System Clock Configuration
     
125.   *         The system Clock is configured as follow :
     
126.   *            System Clock source            = PLL (HSE BYPASS)
     
127.   *            SYSCLK(Hz)                     = 400000000 (CPU Clock)
     
128.   *            HCLK(Hz)                       = 200000000 (AXI and AHBs Clock)
     
129.   *            AHB Prescaler                  = 2
     
130.   *            D1 APB3 Prescaler              = 2 (APB3 Clock  100MHz)
     
131.   *            D2 APB1 Prescaler              = 2 (APB1 Clock  100MHz)
     
132.   *            D2 APB2 Prescaler              = 2 (APB2 Clock  100MHz)
     
133.   *            D3 APB4 Prescaler              = 2 (APB4 Clock  100MHz)
     
134.   *            HSE Frequency(Hz)              = 8000000
     
135.   *            PLL_M                          = 4
     
136.   *            PLL_N                          = 400
     
137.   *            PLL_P                          = 2
     
138.   *            PLL_Q                          = 4
     
139.   *            PLL_R                          = 2
     
140.   *            VDD(V)                         = 3.3
     
141.   *            Flash Latency(WS)              = 4
     
142.   * @param  None
     
143.   * @retval None
     
144.   */
     
145. static void SystemClock_Config(void)
     
146. {
     
147.   RCC_ClkInitTypeDef RCC_ClkInitStruct;
     
148.   RCC_OscInitTypeDef RCC_OscInitStruct;
     
149.   HAL_StatusTypeDef ret = HAL_OK;
     
150.   
     
151.   /*!< Supply configuration update enable */
     
152.   MODIFY_REG(PWR->CR3, PWR_CR3_SCUEN, 0);
     
153. 
     
154.   /* The voltage scaling allows optimizing the power consumption when the device is
     
155.      clocked below the maximum system frequency, to update the voltage scaling value
     
156.      regarding system frequency refer to product datasheet.  */
     
157.   __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
     
158. 
     
159.   while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}
     
160.   
     
161.   /* Enable HSE Oscillator and activate PLL with HSE as source */
     
162.   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
     
163.   RCC_OscInitStruct.HSEState = RCC_HSE_BYPASS;
     
164.   RCC_OscInitStruct.HSIState = RCC_HSI_OFF;
     
165.   RCC_OscInitStruct.CSIState = RCC_CSI_OFF;
     
166.   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
     
167.   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
     
168. 
     
169.   RCC_OscInitStruct.PLL.PLLM = 4;
     
170.   RCC_OscInitStruct.PLL.PLLN = 400;
     
171.   RCC_OscInitStruct.PLL.PLLP = 2;
     
172.   RCC_OscInitStruct.PLL.PLLR = 2;
     
173.   RCC_OscInitStruct.PLL.PLLQ = 4;
     
174. 
     
175.   RCC_OscInitStruct.PLL.PLLVCOSEL = RCC_PLL1VCOWIDE;
     
176.   RCC_OscInitStruct.PLL.PLLRGE = RCC_PLL1VCIRANGE_2;
     
177.   ret = HAL_RCC_OscConfig(&RCC_OscInitStruct);
     
178.   if(ret != HAL_OK)
     
179.   {
     
180.     Error_Handler();
     
181.   }
     
182.   
     
183. /* Select PLL as system clock source and configure  bus clocks dividers */
     
184.   RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_D1PCLK1 | RCC_CLOCKTYPE_PCLK1 | \
     
185.                                  RCC_CLOCKTYPE_PCLK2  | RCC_CLOCKTYPE_D3PCLK1);
     
186. 
     
187.   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
     
188.   RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;
     
189.   RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV2;
     
190.   RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV2;  
     
191.   RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV2;
     
192.   RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV2;
     
193.   RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV2;
     
194.   ret = HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4);
     
195.   if(ret != HAL_OK)
     
196.   {
     
197.     Error_Handler();
     
198.   }
     
199. 
     
200. }
     
201. /**
     
202.   * @brief  Enable External Low Speed Clock (LSE)
     
203.   * @param  None
     
204.   * @retval Status
     
205.   */
     
206. static HAL_StatusTypeDef LSE_ClockEnable(void)
     
207. {
     
208.   RCC_OscInitTypeDef RCC_OscInitStruct;
     
209.   
     
210.   /* Enable LSE clock */
     
211.   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSE;
     
212.   RCC_OscInitStruct.LSEState = RCC_LSE_ON;
     
213.   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
     
214.   return (HAL_RCC_OscConfig(&RCC_OscInitStruct));
     
215. }
     
216. 
     
217. /**
     
218.   * @brief  This function is executed in case of error occurrence.
     
219.   * @param  None
     
220.   * @retval None
     
221.   */
     
222. static void Error_Handler(void)
     
223. {
     
224.   /* Turn LED2 on */
     
225.   BSP_LED_On(LED2);
     
226.   while (1)
     
227.   {
     
228.   }
     
229. }
     
230. 
     
231. /**
     
232.   * @brief  CPU L1-Cache enable.
     
233.   * @param  None
     
234.   * @retval None
     
235.   */
     
236. static void CPU_CACHE_Enable(void)
     
237. {
     
238.   /* Enable I-Cache */
     
239.   SCB_EnableICache();
     
240. 
     
241.   /* Enable D-Cache */
     
242.   SCB_EnableDCache();
     
243. }
     
244. 
     
245. #ifdef  USE_FULL_ASSERT
     
246. 
     
247. /**
     
248.   * @brief  Reports the name of the source file and the source line number
     
249.   *         where the assert_param error has occurred.
     
250.   * @param  file: pointer to the source file name
     
251.   * @param  line: assert_param error line source number
     
252.   * @retval None
     
253.   */
     
254. void assert_failed(uint8_t *file, uint32_t line)
     
255. {
     
256.   /* User can add his own implementation to report the file name and line number,
     
257.      ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
     
258. 
     
259.   /* Infinite loop */
     
260.   while (1)
     
261.   {
     
262.   }
     
263. }

复制代码

hecudashi

非低功耗定时器在外部时钟驱动下在停机模式下能工作吗

eric2013

hecudashi 发表于 2018-8-24 09:13
非低功耗定时器在外部时钟驱动下在停机模式下能工作吗

不能，他们的时钟源不能选择，是固定的APB总线时钟。

hecudashi

定时器有个配置时钟源为外部时钟的功能，我一直有疑惑，配置为外部时钟，内部APB总线时钟还对定时器有什么作用？如果不是一回事，配置为外部时钟时APB总线时钟的作用是什么（操作寄存器？）。看定时器框图也看不出来。

eric2013

hecudashi 发表于 2018-8-24 09:46
定时器有个配置时钟源为外部时钟的功能，我一直有疑惑，配置为外部时钟，内部APB总线时钟还对定时器有什么 ...

通用定时器那个是时钟计数器采用的外部触发源，主要用捕获测量等功能。


而低功耗这个是时钟源，外设基本就是在这个时钟源下工作