为什么使用了串口初始化之后，TIM8的PWM就不能正常输出了？

vention123456 提问时间：2016-12-12 08:36 /

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本帖最后由 vention123456 于 2016-12-12 12:00 编辑

STM32F103RC的芯片，有TIM8的。
随便写了一个串口的初始化函数，和一个TIM8的pwm输出，发现，屏蔽掉串口初始化，TIM8正常PWM输出，开启了usart1初始化，TIM8的PWM就没有输出了。铺上代码：
附件附上CubeMX生成的HAL库工程，做对比

#include "stm32f10x.h"

void uart_init(u32 bound);
void time_init(void);

int main(void)
{
      NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

uart_init(115200);
time_init();

while(1)
      {
      }
}

void uart_init(u32 bound)
{

  GPIO_InitTypeDef       GPIO_InitStructure;
  USART_InitTypeDef    USART_InitStructure;
  NVIC_InitTypeDef       NVIC_InitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE);

      //USART1_TX GPIOA.9
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA.9
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; //PA.10
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
      NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;
      NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
      NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
      NVIC_Init(&NVIC_InitStructure);

      USART_InitStructure.USART_BaudRate = bound;
      USART_InitStructure.USART_WordLength = USART_WordLength_8b;
      USART_InitStructure.USART_StopBits = USART_StopBits_1;
      USART_InitStructure.USART_Parity = USART_Parity_No;
      USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
      USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

  USART_Init(USART1, &USART_InitStructure);
  USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
  USART_Cmd(USART1, ENABLE);

}
void time_init()
{

   GPIO_InitTypeDef          GPIO_InitStructure;
   TIM_TimeBaseInitTypeDef    TIM_TimeBaseStructure;
   TIM_OCInitTypeDef          TIM_OCInitStructure;

RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOC| RCC_APB2Periph_TIM8, ENABLE);

/* TIM8 channels as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOC, &GPIO_InitStructure);

/* Time Base configuration */
TIM_TimeBaseStructure.TIM_Prescaler = 720-1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_Period = 98-1;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 5;
TIM_TimeBaseInit(TIM8, &TIM_TimeBaseStructure);

/* Channels Configuration in Toggle mode */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
TIM_OC1Init(TIM8, &TIM_OCInitStructure);
TIM_OC3Init(TIM8, &TIM_OCInitStructure);
TIM_OC2Init(TIM8, &TIM_OCInitStructure);
TIM_OC4Init(TIM8, &TIM_OCInitStructure);

TIM_CtrlPWMOutputs(TIM8, ENABLE);
TIM_SelectOnePulseMode(TIM8, TIM_OPMode_Repetitive);
TIM_Cmd(TIM8, ENABLE);

}
void USART1_IRQHandler(void)
{
if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
{
u8  Res =USART_ReceiveData(USART1);
}

}