标题: STM32F302的TIM1时钟问题，用8MHz内部HSI老是设置不到72MHz作为TIM1的计数频率值 [打印本页]
作者: 过往云烟    时间: 2018-8-30 20:52
标题: STM32F302的TIM1时钟问题，用8MHz内部HSI老是设置不到72MHz作为TIM1的计数频率值
我看了STM32F10x系列的数据手册，一样的，用内部HSI是没有办法到达72MHz。因为在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


只能选着0啊，对吧！
8MHz/2=4MHz作为PLCC的输入，然后倍频最大值16倍 ， 4MHz * 16 = 64MHz作为系统时钟，给AHB下面的APB1和APB2用。

给一张时钟树的图就秒懂了，我就是没看，还在网上瞎找，谨以此帖，记录苦逼的我，希望大家仔细看数据手册。



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

再附上程序配置段：
  1. //*系统时钟配置**************************************************************
  2. static void SetSysClock(void)
  3. {
  4.   __IO uint32_t StartUpCounter = 0, HSIStatus = 0;

  6. /******************************************************************************/
  7. /*            PLL (clocked by HSI) used as System clock source                */
  8. /******************************************************************************/

  10.   /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration -----------*/
  11.   /* Enable HSI */
  12.   RCC->CR |= ((uint32_t)RCC_CR_HSION);

  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));

  21.   if ((RCC->CR & RCC_CR_HSIRDY) != RESET)
  22.   {
  23.     HSIStatus = (uint32_t)0x01;
  24.   }
  25.   else
  26.   {
  27.     HSIStatus = (uint32_t)0x00;
  28.   }

  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;

  35.      /* HCLK = SYSCLK / 1 */
  36.      RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;

  38.      /* PCLK2 = HCLK / 1 */
  39.      RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;

  41.      /* PCLK1 = HCLK / 2 */
  42.      RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;

  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);

  49.     /* Enable PLL */
  50.     RCC->CR |= RCC_CR_PLLON;

  52.     /* Wait till PLL is ready */
  53.     while((RCC->CR & RCC_CR_PLLRDY) == 0)
  54.     {
  55.                         
  56.     }

  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;

  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. }



  76. //*定时器 1 和 15 配置***********************************************************************

  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);

  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);

  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. }
复制代码
注释有中文，所以乱码了，别介意。
这个定时器是配置了4路互补PWM输出，我用来做步进电机驱动器的程序，现在在调试阶段出了这个问题。现在知道问题所在可以继续往下走了。





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