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標題: STM32F302的TIM1時鐘問題，用8MHz內部HSI老是設置不到72MHz作為TIM1的計數頻率值 [打印本頁]

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作者: 過往云煙    時間: 2018-8-30 20:52
標題: STM32F302的TIM1時鐘問題，用8MHz內部HSI老是設置不到72MHz作為TIM1的計數頻率值
我看了STM32F10x系列的數據手冊，一樣的，用內部HSI是沒有辦法到達72MHz。因為在RCC配置寄存器中
Bit 16 PLLSRC: PLL entry clock source
Set and cleared by software to select PLL clock source. This bit can be written only when
PLL is disabled.
0: HSI/2 selected as PLL input clock
1: HSE/PREDIV selected as PLL input clock (refer to Section 8.4.12: Clock configuration
register 2 (RCC_CFGR2) on page 115


只能選著0啊，對吧！
8MHz/2=4MHz作為PLCC的輸入，然后倍頻最大值16倍 ， 4MHz * 16 = 64MHz作為系統時鐘，給AHB下面的APB1和APB2用。

給一張時鐘樹的圖就秒懂了，我就是沒看，還在網上瞎找，謹以此帖，記錄苦逼的我，希望大家仔細看數據手冊。



1.when the HSI is used as a pll clock input,the maximum system clock frequency that can be achieved is 64MHz.
就是這句話。

再附上程序配置段：

1. //*系統時鐘配置**************************************************************
   
2. static void SetSysClock(void)
   
3. {
   
4.   __IO uint32_t StartUpCounter = 0, HSIStatus = 0;
   
5. 
   
6. /******************************************************************************/
   
7. /*            PLL (clocked by HSI) used as System clock source                */
   
8. /******************************************************************************/
   
9. 
   
10.   /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration -----------*/
    
11.   /* Enable HSI */
    
12.   RCC->CR |= ((uint32_t)RCC_CR_HSION);
    
13. 
    
14.   /* Wait till HSE is ready and if Time out is reached exit */
    
15.   do
    
16.   {
    
17.     HSIStatus = RCC->CR & RCC_CR_HSIRDY;
    
18.     StartUpCounter++;
    
19.   } while((HSIStatus == 0) && (StartUpCounter != HSI_STARTUP_TIMEOUT));
    
20. 
    
21.   if ((RCC->CR & RCC_CR_HSIRDY) != RESET)
    
22.   {
    
23.     HSIStatus = (uint32_t)0x01;
    
24.   }
    
25.   else
    
26.   {
    
27.     HSIStatus = (uint32_t)0x00;
    
28.   }
    
29. 
    
30.   if (HSIStatus == (uint32_t)0x01)
    
31.   {
    
32.     /* Enable Prefetch Buffer and set Flash Latency */
    
33.     FLASH->ACR = FLASH_ACR_PRFTBE | (uint32_t)FLASH_ACR_LATENCY_1;
    
34. 
    
35.      /* HCLK = SYSCLK / 1 */
    
36.      RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
    
37. 
    
38.      /* PCLK2 = HCLK / 1 */
    
39.      RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
    
40. 
    
41.      /* PCLK1 = HCLK / 2 */
    
42.      RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
    
43. 
    
44.     /* PLL configuration */
    
45.     /*SYSCLK = HSI/2 * RCC_CFGR_PLLMULL16  = 64MHz*/
    
46.     RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLMULL | RCC_CFGR_PPRE1 | RCC_CFGR_PPRE2));
    
47.     RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLMULL16 | RCC_CFGR_PPRE1_DIV1 | RCC_CFGR_PPRE2_DIV1);
    
48. 
    
49.     /* Enable PLL */
    
50.     RCC->CR |= RCC_CR_PLLON;
    
51. 
    
52.     /* Wait till PLL is ready */
    
53.     while((RCC->CR & RCC_CR_PLLRDY) == 0)
    
54.     {
    
55.                         
    
56.     }
    
57. 
    
58.     /* Select PLL as system clock source */
    
59.     RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
    
60.     RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;
    
61. 
    
62.     /* Wait till PLL is used as system clock source */
    
63.     while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_PLL)
    
64.     {
    
65.                         
    
66.     }
    
67.   }
    
68.   else
    
69.   { /* If HSE fails to start-up, the application will have wrong clock
    
70.          configuration. User can add here some code to deal with this error */
    
71.   }
    
72. }
    
73. 
    
74. 
    
75. 
    
76. //*定時器 1 和 15 配置***********************************************************************
    
77. 
    
78. void TIM1_Init()
    
79. {
    
80.         /**?????¨ê±?÷*********************************/
    
81.         TIM_TimeBaseInitTypeDef   TIM_TimeBaseStructure;
    
82.         GPIO_InitTypeDef          GPIO_InitStructure;
    
83.         TIM_OCInitTypeDef         TIM_OCInitStructure;
    
84.       
    
85.         RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_TIM15, ENABLE);
    
86.         RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB , ENABLE);
    
87. 
    
88.         //**????????±?ê1?üIOòy?? PB0*************************************
    
89.         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    
90.   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
    
91.   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    
92.   GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    
93.   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    
94.   GPIO_Init(GPIOB, &GPIO_InitStructure);
    
95.         GPIO_SetBits(GPIOB,GPIO_Pin_0);
    
96.       
    
97.         /**????ê?3?òy?? GPIO******************************************/
    
98.         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_12;
    
99.   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    
100.   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
     
101.   GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
     
102.   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
     
103.   GPIO_Init(GPIOA, &GPIO_InitStructure);
     
104. 
     
105.         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
     
106.   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
     
107.   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
     
108.   GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
     
109.   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
     
110.   GPIO_Init(GPIOB, &GPIO_InitStructure);
     
111. //PA9 PA12 PA8 PB13    PB14 PB15 PA10 P
     
112.         /**????GPIO?′ó?1|?ü*****************************/
     
113.         GPIO_PinAFConfig(GPIOA, GPIO_PinSource8,  GPIO_AF_6);
     
114.         GPIO_PinAFConfig(GPIOA, GPIO_PinSource9,  GPIO_AF_6);
     
115.         GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_6);
     
116.         GPIO_PinAFConfig(GPIOA, GPIO_PinSource12, GPIO_AF_6);
     
117.         GPIO_PinAFConfig(GPIOB, GPIO_PinSource1,  GPIO_AF_6);
     
118.         GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_6);
     
119.         GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_1);
     
120.         GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_2);
     
121.         //*TIM1*?¨ê±?÷????**********************************/
     
122.         TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
     
123.         TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
     
124.         TIM_TimeBaseStructure.TIM_Period = 2560;
     
125.         TIM_TimeBaseStructure.TIM_Prescaler = TIM_CKD_DIV1;
     
126.         TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
     
127.         TIM_TimeBaseInit(TIM1,&TIM_TimeBaseStructure);
     
128.          
     
129.         //*TIM15*?¨ê±?÷????**********************************/
     
130.         TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
     
131.         TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
     
132.         TIM_TimeBaseStructure.TIM_Period = 2560;
     
133.         TIM_TimeBaseStructure.TIM_Prescaler = TIM_CKD_DIV1;
     
134.         TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
     
135.         TIM_TimeBaseInit(TIM15,&TIM_TimeBaseStructure);
     
136.          
     
137.                
     
138.         /**?????¨ê±?÷PWM CH1????*PA8*********************************************/
     
139.         TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
     
140.         TIM_OCInitStructure.TIM_Pulse = 0;
     
141.         TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
     
142.         TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
     
143.         TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Reset;
     
144.         /**?????¨ê±?÷PWM CH1N????*PB13******************************************************/
     
145.         TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
     
146.         TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
     
147.         TIM_OCInitStructure.TIM_OCNIdleState =TIM_OCNIdleState_Reset;
     
148.         TIM_OC1Init(TIM1, &TIM_OCInitStructure);  
     
149.         TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);  
     
150.       
     
151.         /**?????¨ê±?÷PWM CH2????*PA9*********************************************/
     
152.         TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
     
153.         TIM_OCInitStructure.TIM_Pulse = 0;
     
154.         TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
     
155.         TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
     
156.         TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Reset;
     
157.         /**?????¨ê±?÷PWM CH2N????*PA12******************************************************/
     
158.         TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
     
159.         TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
     
160.         TIM_OCInitStructure.TIM_OCNIdleState =TIM_OCNIdleState_Reset;
     
161.         TIM_OC2Init(TIM1, &TIM_OCInitStructure);  
     
162.         TIM_OC2PreloadConfig(TIM1, TIM_OCPreload_Enable);  
     
163.       
     
164.         /**?????¨ê±?÷PWM CH3????*PA10*********************************************/
     
165.         TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
     
166.         TIM_OCInitStructure.TIM_Pulse = 0;
     
167.         TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
     
168.         TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
     
169.         TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Reset;
     
170.         /**?????¨ê±?÷PWM CH3N????*PB1******************************************************/
     
171.         TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
     
172.         TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
     
173.         TIM_OCInitStructure.TIM_OCNIdleState =TIM_OCNIdleState_Reset;
     
174.         TIM_OC3Init(TIM1, &TIM_OCInitStructure);  
     
175.         TIM_OC3PreloadConfig(TIM1, TIM_OCPreload_Enable);  
     
176.       
     
177.       
     
178.         /*TIM15*?????¨ê±?÷PWM CH1????*PB14*********************************************/
     
179.         TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
     
180.         TIM_OCInitStructure.TIM_Pulse = 0;
     
181.         TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
     
182.         TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
     
183.         TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Reset;
     
184.         /*TIM15*?????¨ê±?÷PWM CH1N????*PB15******************************************************/
     
185.         TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
     
186.         TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
     
187.         TIM_OCInitStructure.TIM_OCNIdleState =TIM_OCNIdleState_Reset;
     
188.         TIM_OC1Init(TIM15, &TIM_OCInitStructure);  
     
189.         TIM_OC1PreloadConfig(TIM15, TIM_OCPreload_Enable);  
     
190.       
     
191.         /*?????¨ê±?÷*/
     
192.         TIM_CtrlPWMOutputs(TIM15,ENABLE);        
     
193.         TIM_CtrlPWMOutputs(TIM1,ENABLE);        
     
194.         TIM_Cmd(TIM1,ENABLE);
     
195.         TIM_Cmd(TIM15,ENABLE);
     
196. }
     

復制代碼

注釋有中文，所以亂碼了，別介意。
這個定時器是配置了4路互補PWM輸出，我用來做步進電機驅動器的程序，現在在調試階段出了這個問題。現在知道問題所在可以繼續往下走了。

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