STM32F103vc 的PB8没有PWM输出疑问

只看该作者 · 2014-12-5 14:32

本帖最后由 billy_2005 于 2014-12-5 14:42 编辑

大家好，我用STM32F103vc的定时器4,发现PB9有输出，但PB8总是保持低电平，是不是哪里要设置一下，谢谢。
下面是我的初始化代码。

      //PWM~定时器4
      RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
      RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB|RCC_APB2Periph_AFIO, ENABLE);

      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9|GPIO_Pin_8;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //复用推挽输出
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_Init(GPIOB, &GPIO_InitStructure);

      TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值       80K
      TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值  不分频
      TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim
      TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上计数模式
      TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位

      TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2
      TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能//正向通道有效//       TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;//反向通道无效

      TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值
      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性
      TIM_OC1Init(TIM4, &TIM_OCInitStructure);  //根据TIM_OCInitStruct中指定的参数初始化外设TIMx
      TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable);  //使能TIMx在CCR2上的预装载寄存器

      TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值
      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性
      TIM_OC2Init(TIM4, &TIM_OCInitStructure);  //根据TIM_OCInitStruct中指定的参数初始化外设TIMx
      TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);  //使能TIMx在CCR2上的预装载寄存器

      TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值
      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性
      TIM_OC3Init(TIM4, &TIM_OCInitStructure);  //根据TIM_OCInitStruct中指定的参数初始化外设TIMx
      TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);  //使能TIMx在CCR2上的预装载寄存器

      TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值
      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性
      TIM_OC4Init(TIM4, &TIM_OCInitStructure);  //根据TIM_OCInitStruct中指定的参数初始化外设TIMx
      TIM_OC4PreloadConfig(TIM4, TIM_OCPreload_Enable);  //使能TIMx在CCR2上的预装载寄存器

      TIM_ARRPreloadConfig(TIM4, ENABLE); //使能TIMx在ARR上的预装载寄存器

      TIM_Cmd(TIM4, ENABLE);  //使能TIMx外设

3万 · 2014-12-6 11:33

TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值
这个改下;

只看该作者 · 2014-12-6 14:47

mmuuss586 发表于 2014-12-6 11:33
TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值
这个改下;

这个只是初始化的值，初始化后我加上了一句 TIM_SetCompare3(TIM4,40); TIM_SetCompare4(TIM4,40); ，不明为什么只有第四路没波形输出

3万 · 2014-12-6 17:15

/*******************************************************************************
      TIM3配置  motor--pwm  2kHz
*******************************************************************************/
void TIM3_Configuration(void)
{
/* -----------------------------------------------------------------------
TIM3 Configuration: generate 4 PWM signals with 4 different duty cycles:
TIM3CLK = 18 MHz, Prescaler = 0x0, TIM3 counter clock = 36 MHz
TIM3 ARR Register = 999 => TIM3 Frequency = TIM3 counter clock/(ARR + 1)
TIM3 Frequency = 36 KHz.
TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR)* 100 = 50%
TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR)* 100 = 37.5%
TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR)* 100 = 25%
TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR)* 100 = 12.5%
  ----------------------------------------------------------------------- */
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
  TIM_OCInitTypeDef  TIM_OCInitStructure;
  /* Time base configuration */
  TIM_TimeBaseStructure.TIM_Period = 3000; //72000/(3599+1)
  TIM_TimeBaseStructure.TIM_Prescaler = 9;    // TIMCLK/2
  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV4;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  /* PWM1 Mode configuration: Channel-3*/
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = 3000;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High ;
  TIM_OC3Init(TIM3, &TIM_OCInitStructure);
  TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);

  /* PWM1 Mode configuration: Channel-4 */
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = 3000;
  TIM_OC4Init(TIM3, &TIM_OCInitStructure);
  TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);

  TIM_ARRPreloadConfig(TIM3, ENABLE);
  TIM_Cmd(TIM3, ENABLE);
}
这是我的程序；

3万 · 2014-12-6 17:16

你改成PWM模式1试下看看；
另外OC1和2没用到的话，先注释掉吧；

STM32F103vc 的PB8没有PWM输出疑问

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