STM32一定时器产生不同频率的PWM

时间:2021-06-20 19:33:25

平时记性实在太差,调试完的程序,过两天又忘了,往往需要一阵子才能想起来,有时以前的资料找不到了,更是恼火,不得不重复到网上搜索。刚刚调试成功了一个类型的程序,立刻记下来,呵呵,不要又忘记了。


    STM32产生PWM是非常的方便的,要需要简单的设置定时器,即刻产生!当然,简单的设置对于新手来产,也是麻烦的,主要包括:


(1)使能定时器时钟:RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);


(2)定义相应的GPIO:




GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //下拉接地,检测输入的高电平
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度
GPIO_Init(GPIOA, &GPIO_InitStructure);


GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; 
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度
GPIO_Init(GPIOA, &GPIO_InitStructure);


(3)如果是产生PWM(频率不变,占空比可变),记得打开PWM控制,在TIM_Configuration()中。


TIM_Cmd(TIM3,ENABLE);




TIM_CtrlPWMOutputs(TIM1,ENABLE);


利用定时器产生不同频率的PWM


  有时候,需要产生不同频率的PWM,这个时候,设置与产生相同PWM的程序,有关键的不一样。


(一) 设置的原理


    利用改变定时器输出比较通道的捕获值,当输出通道捕获值产生中断时,在中断中将捕获值改变,这时, 输出的I/O会产生一个电平翻转,利用这种办法,实现不同频率的PWM输出。


(二)关键设置


在定时器设置中:TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable);


在中断函数中: if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET)
    {
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);
  capture = TIM_GetCapture2(TIM3);
    TIM_SetCompare2(TIM3, capture + Key_Value);
}


一个定时器四个通道,分别产生不同频率(这个例子网上也有)




vu16 CCR1_Val = 32768;
vu16 CCR2_Val = 16384;
vu16 CCR3_Val = 8192;
vu16 CCR4_Val = 4096;


void TIM_Configuration(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;


RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);






TIM_TimeBaseStructure.TIM_Period = 65535;       
TIM_TimeBaseStructure.TIM_Prescaler = 2;     
TIM_TimeBaseStructure.TIM_ClockDivision = 0; 
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;


TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);




TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;      //PWM模式2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //正向通道有效
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;//反向通道无效
TIM_OCInitStructure.TIM_Pulse = CCR1_Val;        //占空时间
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;    //输出极性
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;    //互补端的极性
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;


TIM_OC1Init(TIM2,&TIM_OCInitStructure);        //通道1
TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Disable);


TIM_OCInitStructure.TIM_Pulse = CCR2_Val;        //占空时间
TIM_OC2Init(TIM2,&TIM_OCInitStructure);        //通道2
TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Disable);


TIM_OCInitStructure.TIM_Pulse = CCR3_Val;        //占空时间
TIM_OC3Init(TIM2,&TIM_OCInitStructure);        //通道3
TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Disable);


TIM_OCInitStructure.TIM_Pulse = CCR4_Val;        //占空时间
TIM_OC4Init(TIM2,&TIM_OCInitStructure);        //通道4
TIM_OC4PreloadConfig(TIM2, TIM_OCPreload_Disable);






TIM_Cmd(TIM2,ENABLE);




//TIM_CtrlPWMOutputs(TIM2,ENABLE);


 
TIM_ITConfig(TIM2, TIM_IT_CC1 | TIM_IT_CC2 | TIM_IT_CC3 | TIM_IT_CC4, ENABLE);


}


void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;






RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);






GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6|GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //开漏输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度
GPIO_Init(GPIOA, &GPIO_InitStructure);






GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //开漏输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度
GPIO_Init(GPIOB, &GPIO_InitStructure);




GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;  //上拉输入
GPIO_Init(GPIOA, &GPIO_InitStructure);




GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;  //上拉输入
GPIO_Init(GPIOC, &GPIO_InitStructure);




GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;  //上拉输入
GPIO_Init(GPIOB, &GPIO_InitStructure);




GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;


GPIO_Init(GPIOA, &GPIO_InitStructure);
}


void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;




NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);


NVIC_InitStructure.NVIC_IRQChannel=TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;
NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
NVIC_Init(&NVIC_InitStructure);
}


u16 capture = 0;
extern vu16 CCR1_Val;
extern vu16 CCR2_Val;
extern vu16 CCR3_Val;
extern vu16 CCR4_Val;


void TIM2_IRQHandler(void)
{




if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET)
{
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC1 );
capture = TIM_GetCapture1(TIM2);
TIM_SetCompare1(TIM2, capture + CCR1_Val );
}




if (TIM_GetITStatus(TIM2, TIM_IT_CC2) != RESET)
{
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
capture = TIM_GetCapture2(TIM2);
    TIM_SetCompare2(TIM2, capture + CCR2_Val);
}




if (TIM_GetITStatus(TIM2, TIM_IT_CC3) != RESET)
{
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC3);
capture = TIM_GetCapture3(TIM2);
    TIM_SetCompare3(TIM2, capture + CCR3_Val);
}




if (TIM_GetITStatus(TIM2, TIM_IT_CC4) != RESET)
{
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC4);
capture = TIM_GetCapture4(TIM2);
    TIM_SetCompare4(TIM2, capture + CCR4_Val);
}


}
一个定时器一个通道,产生不同频率


其它的设置都一样,就是在主函数中修改一个参数,然后在定时器中断中,根据这个参数,改变频率。


#include "stm32lib\\stm32f10x.h"
#include "hal.h"
volatile u16 Key_Value=1000;  //用于保存按键相应的PWM波占空比值
int main(void)
{
ChipHalInit();
ChipOutHalInit();
while(1)

  if( (!Get_Key_Up)&(!Get_Key_Down)&(!Get_Key_Left)&(!Get_Key_Right)&(!Get_Key_Ctrl) )
  {
    Key_Value=12000;
  }
  else
  {
    if(Get_Key_Up)    //按键前进按下 ,对应1kHz
    {
    Key_Value=6000;
    }
    else if(Get_Key_Down)  //按键后退按下 ,对应2kHz
    {
      Key_Value=3000;
    }
    Delay_Ms(20);      //10ms延时


    if(Get_Key_Left)    //按键左转按下,对应3kHz
    {
    Key_Value=2000;
    }
    else if(Get_Key_Right) //按键右转按下,对应4kHz
    {
      Key_Value=1500;
    } 
    Delay_Ms(20);      //10ms延时


    if(Get_Key_Ctrl)    //按键控制按下,对应5kHz
    {
      Key_Value=1200;
    }
    Delay_Ms(20);      //10ms延时
  }
}
}
extern volatile u16 Key_Value;
u16 capture=0;
void TIM3_IRQHandler(void)
{


if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET)
{
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);
capture = TIM_GetCapture2(TIM3);
    TIM_SetCompare2(TIM3, capture + Key_Value);
}
}
void TIM3_Configuration(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;




RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);




TIM_TimeBaseStructure.TIM_Prescaler = 5;      //预分频(时钟分频)72M/6=12M
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //向上计数
TIM_TimeBaseStructure.TIM_Period = 65535;        //装载值选择最大
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0x0;
TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure);




TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;      //PWM模式2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //正向通道有效
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;//反向通道无效
TIM_OCInitStructure.TIM_Pulse = Key_Value;        //占空时间
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;    //输出极性
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;    //互补端的极性
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;


TIM_OC2Init(TIM3,&TIM_OCInitStructure);        //通道2
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable);




TIM_Cmd(TIM3,ENABLE);




//TIM_CtrlPWMOutputs(TIM1,ENABLE);
TIM_ITConfig(TIM3, TIM_IT_CC2 , ENABLE);
}


注意:在计算PWM频率的时候,TIMx的时钟都是72Mhz,分频后,因为翻转两次才能形成一个PWM波,因为,PWM的频率是捕获改变频率的1/2。