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STM32定时器产生不同频率的PWM

发布时间:2020-05-21 发布时间:
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 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!


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


(2)定义相应的GPIO:


 /* PA2,3,4,5,6输出->Key_Up,Key_Down,Key_Left,Key_Right,Key_Ctrl */


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);


/* PA7用于发出PWM波 */


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);


/* TIM1 Main Output 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;


  /* TIM2 clock enable */


  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);


  /* ---------------------------------------------------------------


  TIM2 Configuration: Output Compare Toggle Mode:


  TIM2CLK = 36 MHz, Prescaler = 0x2, TIM2 counter clock = 12 MHz


  CC1 update rate = TIM2 counter clock / CCR1_Val = 366.2 Hz


  CC2 update rate = TIM2 counter clock / CCR2_Val = 732.4 Hz


  CC3 update rate = TIM2 counter clock / CCR3_Val = 1464.8 Hz


  CC4 update rate = TIM2 counter clock / CCR4_Val = 2929.6 Hz


  --------------------------------------------------------------- */


  /* Time base configuration */


  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);


  /* Channel 1 Configuration in PWM mode */


  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);


  /* TIM2 counter enable */


  TIM_Cmd(TIM2,ENABLE);


 


  /* TIM2 Main Output Enable */


  //TIM_CtrlPWMOutputs(TIM2,ENABLE);


   /* TIM IT 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;


 


/*允许总线CLOCK,在使用GPIO之前必须允许相应端的时钟.


从STM32的设计角度上说,没被允许的端将不接入时钟,也就不会耗能,


这是STM32节能的一种技巧,*/


 


RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);


RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);


RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);


RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);


 


 


/* PA2,3,4,5,6,7输出->LED1,LED2,LED3,LED4,LED5,LED6 */


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);


 


 


/* PB0,1输出->LED7,LED8*/


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);


 


/* PA0,1->KEY_LEFT,KEY_RIGHT*/


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);


 


/* PC13->KEY_UP*/


GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;


GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;? //上拉输入


GPIO_Init(GPIOC, &GPIO_InitStructure);


 


/* PB5->KEY_DOWN*/


GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;


GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;? //上拉输入


GPIO_Init(GPIOB, &GPIO_InitStructure);


 


/* GPIOA Configuration:TIM2 Channel1, 2, 3 and 4 in Output */


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;


 


/* Configure one bit for preemption priority */


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)


{


/* TIM2_CH1 toggling with frequency = 183.1 Hz */


if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET)


{


  TIM_ClearITPendingBit(TIM2, TIM_IT_CC1 );


  capture = TIM_GetCapture1(TIM2);


  TIM_SetCompare1(TIM2, capture + CCR1_Val );



/* TIM2_CH2 toggling with frequency = 366.2 Hz */


if (TIM_GetITStatus(TIM2, TIM_IT_CC2) != RESET)


{


  TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);


  capture = TIM_GetCapture2(TIM2);


  TIM_SetCompare2(TIM2, capture + CCR2_Val);


}


 


/* TIM2_CH3 toggling with frequency = 732.4 Hz */


if (TIM_GetITStatus(TIM2, TIM_IT_CC3) != RESET)


{


   TIM_ClearITPendingBit(TIM2, TIM_IT_CC3);


  capture = TIM_GetCapture3(TIM2);


  TIM_SetCompare3(TIM2, capture + CCR3_Val);


}


 


/* TIM2_CH4 toggling with frequency = 1464.8 Hz */


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)


{


/* TIM2_CH2 toggling with frequency = 366.2 Hz */


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;


 


/* TIM2 clock enable */


RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);


 


/*TIM1时钟配置*/


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);


 


/* Channel 1 Configuration in PWM mode */


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);


/* TIM1 counter enable */


  TIM_Cmd(TIM3,ENABLE);


/* TIM1 Main Output 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。


关键字:STM32  定时器  不同频率  PWM

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