STM32F103输出PWM

只看该作者 · 2020-9-1 16:51

STM32F103的TIM3输出4路PWM，500ms中断一次，想让图片中红框区域的波形是始终保持高电平或者低电平，不要变化，求解！！

只看该作者 · 2020-9-1 16:55

中断函数如下

void TIM4_Int_Init(u16 arr,u16 psc)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE); //时钟使能

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    计数到5000为500ms
TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值  10Khz的计数频率
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_ITConfig(TIM4,TIM_IT_Update,ENABLE ); //使能指定的TIM3中断,允许更新中断

NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;  //TIM3中断
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  //先占优先级0级
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;  //从优先级3级
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能
NVIC_Init(&NVIC_InitStructure);  //根据NVIC_InitStruct中指定的参数初始化外设NVIC寄存器

TIM_Cmd(TIM4, ENABLE);  //使能TIMx外设

}
//定时器3中断服务程序
void TIM4_IRQHandler(void) //TIM3中断
{
static char flag = 0;
if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET) //检查指定的TIM中断发生与否:TIM 中断源
{
   TIM_ClearITPendingBit(TIM4, TIM_IT_Update  );  //清除TIMx的中断待处理位:TIM 中断源
   LED1=!LED1;
if(flag == 0)
{

TIM_Cmd(TIM3, DISABLE);




flag = 1;
} else
{
flag = 0;
TIM_Cmd(TIM3, ENABLE);

}
}

}

只看该作者 · 2020-9-1 16:55

PWM输出：

void TIM3_PWM_Init(u16 arr,u16 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //使能定时器3时钟
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA  | RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);  //使能GPIO外设和AFIO复用功能模块时钟

// GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射  TIM3_CH2->PB5

//设置该引脚为复用输出功能,输出TIM3 CH2的PWM脉冲波形 GPIOB.5
GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_7 | GPIO_Pin_6 ; //TIM_CH1和TIM_CH2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //复用推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIO

GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_0 | GPIO_Pin_1 ; //TIM_CH3和TIM_CH4
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);//初始化GPIO

//初始化TIM3
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
TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值
TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_CenterAligned1  ;  //TIM向上向下计数模式
TIM_TimeBaseInit(TIM3, &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
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High ; //输出极性:TIM输出比较极性高
TIM_OC1Init(TIM3, &TIM_OCInitStructure);  //根据T指定的参数初始化外设TIM3 OC1

//初始化TIM3 Channel2 PWM模式
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
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High ; //输出极性:TIM输出比较极性高
TIM_OC2Init(TIM3, &TIM_OCInitStructure);  //根据T指定的参数初始化外设TIM3 OC2

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //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
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High ; //输出极性:TIM输出比较极性高
TIM_OC3Init(TIM3, &TIM_OCInitStructure);  //根据T指定的参数初始化外设TIM3 OC3

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //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
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High ; //输出极性:TIM输出比较极性高
TIM_OC4Init(TIM3, &TIM_OCInitStructure);  //根据T指定的参数初始化外设TIM3 OC4

TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);  //使能TIM3在CCR2上的预装载寄存器
TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);  //使能TIM3在CCR2上的预装载寄存器

TIM_Cmd(TIM3, ENABLE);  //使能TIM3

}