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:
代码:
- //*系统时钟配置**************************************************************
- static void SetSysClock(void)
- {
- __IO uint32_t StartUpCounter = 0, HSIStatus = 0;
- /******************************************************************************/
- /* PLL (clocked by HSI) used as System clock source */
- /******************************************************************************/
- /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration -----------*/
- /* Enable HSI */
- RCC->CR |= ((uint32_t)RCC_CR_HSION);
- /* Wait till HSE is ready and if Time out is reached exit */
- do
- {
- HSIStatus = RCC->CR & RCC_CR_HSIRDY;
- StartUpCounter++;
- } while((HSIStatus == 0) && (StartUpCounter != HSI_STARTUP_TIMEOUT));
- if ((RCC->CR & RCC_CR_HSIRDY) != RESET)
- {
- HSIStatus = (uint32_t)0x01;
- }
- else
- {
- HSIStatus = (uint32_t)0x00;
- }
- if (HSIStatus == (uint32_t)0x01)
- {
- /* Enable Prefetch Buffer and set Flash Latency */
- FLASH->ACR = FLASH_ACR_PRFTBE | (uint32_t)FLASH_ACR_LATENCY_1;
- /* HCLK = SYSCLK / 1 */
- RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
- /* PCLK2 = HCLK / 1 */
- RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
- /* PCLK1 = HCLK / 2 */
- RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
- /* PLL configuration */
- /*SYSCLK = HSI/2 * RCC_CFGR_PLLMULL16 = 64MHz*/
- RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLMULL | RCC_CFGR_PPRE1 | RCC_CFGR_PPRE2));
- RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLMULL16 | RCC_CFGR_PPRE1_DIV1 | RCC_CFGR_PPRE2_DIV1);
- /* Enable PLL */
- RCC->CR |= RCC_CR_PLLON;
- /* Wait till PLL is ready */
- while((RCC->CR & RCC_CR_PLLRDY) == 0)
- {
-
- }
- /* Select PLL as system clock source */
- RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
- RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;
- /* Wait till PLL is used as system clock source */
- while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_PLL)
- {
-
- }
- }
- else
- { /* If HSE fails to start-up, the application will have wrong clock
- configuration. User can add here some code to deal with this error */
- }
- }
- //*定时器 1 和 15 配置***********************************************************************
- void TIM1_Init()
- {
- /**?????¨ê±?÷*********************************/
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- GPIO_InitTypeDef GPIO_InitStructure;
- TIM_OCInitTypeDef TIM_OCInitStructure;
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_TIM15, ENABLE);
- RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB , ENABLE);
- //**????????±?ê1?üIOòy?? PB0*************************************
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
- GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
- GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOB, &GPIO_InitStructure);
- GPIO_SetBits(GPIOB,GPIO_Pin_0);
-
- /**????ê?3?òy?? GPIO******************************************/
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_12;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
- GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
- GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOA, &GPIO_InitStructure);
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
- GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
- GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOB, &GPIO_InitStructure);
- //PA9 PA12 PA8 PB13 PB14 PB15 PA10 P
- /**????GPIO?′ó?1|?ü*****************************/
- GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_6);
- GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_6);
- GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_6);
- GPIO_PinAFConfig(GPIOA, GPIO_PinSource12, GPIO_AF_6);
- GPIO_PinAFConfig(GPIOB, GPIO_PinSource1, GPIO_AF_6);
- GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_6);
- GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_1);
- GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_2);
- //*TIM1*?¨ê±?÷????**********************************/
- TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
- TIM_TimeBaseStructure.TIM_Period = 2560;
- TIM_TimeBaseStructure.TIM_Prescaler = TIM_CKD_DIV1;
- TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
- TIM_TimeBaseInit(TIM1,&TIM_TimeBaseStructure);
-
- //*TIM15*?¨ê±?÷????**********************************/
- TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
- TIM_TimeBaseStructure.TIM_Period = 2560;
- TIM_TimeBaseStructure.TIM_Prescaler = TIM_CKD_DIV1;
- TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
- TIM_TimeBaseInit(TIM15,&TIM_TimeBaseStructure);
-
-
- /**?????¨ê±?÷PWM CH1????*PA8*********************************************/
- TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
- TIM_OCInitStructure.TIM_Pulse = 0;
- TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
- TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
- TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Reset;
- /**?????¨ê±?÷PWM CH1N????*PB13******************************************************/
- TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
- TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
- TIM_OCInitStructure.TIM_OCNIdleState =TIM_OCNIdleState_Reset;
- TIM_OC1Init(TIM1, &TIM_OCInitStructure);
- TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);
-
- /**?????¨ê±?÷PWM CH2????*PA9*********************************************/
- TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
- TIM_OCInitStructure.TIM_Pulse = 0;
- TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
- TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
- TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Reset;
- /**?????¨ê±?÷PWM CH2N????*PA12******************************************************/
- TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
- TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
- TIM_OCInitStructure.TIM_OCNIdleState =TIM_OCNIdleState_Reset;
- TIM_OC2Init(TIM1, &TIM_OCInitStructure);
- TIM_OC2PreloadConfig(TIM1, TIM_OCPreload_Enable);
-
- /**?????¨ê±?÷PWM CH3????*PA10*********************************************/
- TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
- TIM_OCInitStructure.TIM_Pulse = 0;
- TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
- TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
- TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Reset;
- /**?????¨ê±?÷PWM CH3N????*PB1******************************************************/
- TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
- TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
- TIM_OCInitStructure.TIM_OCNIdleState =TIM_OCNIdleState_Reset;
- TIM_OC3Init(TIM1, &TIM_OCInitStructure);
- TIM_OC3PreloadConfig(TIM1, TIM_OCPreload_Enable);
-
-
- /*TIM15*?????¨ê±?÷PWM CH1????*PB14*********************************************/
- TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
- TIM_OCInitStructure.TIM_Pulse = 0;
- TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
- TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
- TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Reset;
- /*TIM15*?????¨ê±?÷PWM CH1N????*PB15******************************************************/
- TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
- TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
- TIM_OCInitStructure.TIM_OCNIdleState =TIM_OCNIdleState_Reset;
- TIM_OC1Init(TIM15, &TIM_OCInitStructure);
- TIM_OC1PreloadConfig(TIM15, TIM_OCPreload_Enable);
-
- /*?????¨ê±?÷*/
- TIM_CtrlPWMOutputs(TIM15,ENABLE);
- TIM_CtrlPWMOutputs(TIM1,ENABLE);
- TIM_Cmd(TIM1,ENABLE);
- TIM_Cmd(TIM15,ENABLE);
- }
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。