stm32定时器部分 产生spwm波

用的是野火的例程

main函数：

#define CLI() __set_PRIMASK(1)       
#define SEI() __set_PRIMASK(0)    

int main(void)
{ 
 CLI();
 SEI();
 
 TIM34_PWM_Init();
 
 while (1)
 {

 }
}

 

bsp_pwm_output.c用户文件

void TIM3_PWM_Init(void)
{
 TIM34_GPIO_Config();
 TIM34_Mode_Config();

}

 

 

static void TIM34_GPIO_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

 
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3|RCC_APB1Periph_TIM4|RCC_APB2Periph_AFIO, ENABLE);

 
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

 
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_6 | GPIO_Pin_7;
  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);
}
其中，引脚PA6和PA7的复用功能就是TIM3的CH1通道，和CH2通道。所以要开启复用时钟。同时要注意，定时器的时钟不是直接来自APB1或APB2，而是来自于输入为APB1或APB2的一个倍频器。使用任何一个外设都必须打开相应的时钟。这样的好处就是，如果不使用一个外设的时候，就把它的时钟关掉，从而可以降低系统的功耗，达到节能，实现低功耗的效果。具体见http://blog.csdn.net/yx_l128125/article/details/7879506，这里TIM3，4为APB1的2倍频后，时钟为72MHZ。

static void TIM34_Mode_Config(void)
{
        TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
        TIM_OCInitTypeDef     TIM_OCInitStructure;
         TIM_BDTRInitTypeDef   TIM_BDTRInitStructure;
         NVIC_Configuration();

           
        
                 
         TIM_TimeBaseStructure.TIM_Period = 7199;//产生的spwm波的周期为T=1*7200/72M=100us(10KHz)
        TIM_TimeBaseStructure.TIM_Prescaler = 0;//设置预分频：不预分频，即为72MHz
         TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;//设置时钟分频系数：不分频(这里用不到)
        TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;     //向上计数模式
         TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;//不懂什么意思
         TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);//初始化定时器3的基础数据
        
         TIM_DeInit(TIM4);   //复位TIM4定时器，使之进入初始状态   其功能为复位外设PPP的所有寄存器至缺省值         
         TIM_TimeBaseStructure.TIM_Period=1;  //自动装载寄存器的值 
         TIM_TimeBaseStructure.TIM_Prescaler= 3599;   //时钟预分频数 使TIM4_CLK=20KHz
         TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;//采样分频：TIM4每次定时的时间T=2*3600/72M=100us
         TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;//向上计数模式
         TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);//初始化定时器4的基础数据
      
         TIM_ClearFlag(TIM4, TIM_FLAG_Update); //清除中断位
         TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE); //允许TIM4中断   

 

        
        TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;//配置为PWM模式1  
         TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;//  开启oc*输出到对应引脚
         TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;//互补输出使能
         TIM_OCInitStructure.TIM_Pulse =50* 7200 / 100;//占空比为50%
         TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;//当定时器计数值小于CCR1_Val时为高电平(极性为正)
         TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;
         TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
         TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;
         TIM_OC1Init(TIM3, &TIM_OCInitStructure);
         TIM_OC2Init(TIM3, &TIM_OCInitStructure); //使能TIM3的通道1和通道2            
        
         TIM_BDTRInitStructure.TIM_OSSRState = TIM_OSSRState_Enable;
         TIM_BDTRInitStructure.TIM_OSSIState = TIM_OSSIState_Enable;
         TIM_BDTRInitStructure.TIM_LOCKLevel = TIM_LOCKLevel_1;
         TIM_BDTRInitStructure.TIM_DeadTime = 12;
         TIM_BDTRInitStructure.TIM_Break = TIM_Break_Disable;
         TIM_BDTRInitStructure.TIM_BreakPolarity = TIM_BreakPolarity_High;
         TIM_BDTRInitStructure.TIM_AutomaticOutput = TIM_AutomaticOutput_Enable;
         TIM_BDTRConfig(TIM3, &TIM_BDTRInitStructure);
    
         TIM_CtrlPWMOutputs(TIM3, ENABLE); //开启定时器3的PWM模式

         TIM_Cmd(TIM3, ENABLE);                   //使能定时器3
        TIM_Cmd(TIM4, ENABLE);                   //使能定时器3
 
}

中断的初始化函数

static void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
 
 
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
 
 
  NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

stm32f10x_it.c 中断路径处理

void TIM4_IRQHandler(void)·
{
 static vu16 sign = 0;
 static vu16 Counter_sine=0;
 static vu16 Duty_Cycle_sinewavetable[128]={
  0x0,0x83,0x105,0x187,0x209,
  0x28A,0x30A,0x38A,0x409,0x486,
  0x502,0x57D,0x5F7,0x66F,0x6E5,
  0x75A,0x7CC,0x83D,0x8AB,0x917,
  0x981,0x9E8,0xA4D,0xAAF,0xB0E,
  0xB6B,0xBC4,0xC1B,0xC6E,0xCBE,
  0xD0B,0xD54,0xD9A,0xDDD,0xE1C,
  0xE57,0xE8F,0xEC3,0xEF3,0xF1F,
  0xF48,0xF6C,0xF8D,0xFA9,0xFC2,
  0xFD6,0xFE6,0xFF3,0xFFB,0xFFF,
  0xFFF,0xFFB,0xFF3,0xFE6,0xFD6,
  0xFC2,0xFA9,0xF8D,0xF6C,0xF48,
  0xF1F,0xEF3,0xEC3,0xE8F,0xE57,
  0xE1C,0xDDD,0xD9A,0xD54,0xD0B,
  0xCBE,0xC6E,0xC1B,0xBC4,0xB6B,
  0xB0E,0xAAF,0xA4D,0x9E8,0x981,
   0x917,0x8AB,0x83D,0x7CC,0x75A,
   0x6E5,0x66F,0x5F7,0x57D,0x502,
   0x486,0x409,0x38A,0x30A,0x28A,
   0x209,0x187,0x105,0x83,0x0};
 if ( TIM_GetITStatus(TIM4 , TIM_IT_Update) == SET)
 {
  if(sign == 0)
  {
         TIM_SetCompare1(TIM3,Duty_Cycle_sinewavetable[Counter_sine]);
         TIM_SetCompare2(TIM3,0);
         Counter_sine++;
         if(Counter_sine==100)  //
         {
              Counter_sine=0;
              sign = 1;
         }
  }else{
         TIM_SetCompare1(TIM3,0);
         TIM_SetCompare2(TIM3,Duty_Cycle_sinewavetable[Counter_sine]);
         Counter_sine++;
         if(Counter_sine==100)
         {
              Counter_sine=0;
              sign = 0; 
         }
   }
 }
 TIM_ClearITPendingBit(TIM4 , TIM_FLAG_Update);
}

spwm波产生的原理就是，按正弦规律改变pwm的波的占空比，滤出的基波的频率是改变占空比的频率。

TIM4计时溢出中断，每中断一次，在中断函数中，改变TIM3的比较寄存器的值，即修改占空比。

TIM4_CLK的中断频率是10Khz,又半个周期采样100个点，即半个周期要改100次占空比，也即1个周期改200次占空比，所以改变占空比的频率是10KHZ/200=50hz。基波频率为50hz。注意这个表示只有半个周期的。

 中间还有很多不懂的地方，

比如

TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;//互补输出使能是干什么的？我把它去掉也没什么变化啊？
 TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;
这两句也不懂。

TIM_OCInitStructure.TIM_Pulse =50* 7200 / 100;//占空比为50%占空比不是都随着变化了？为什么还要再设置一个50%的占空比？
 TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;//当定时器计数值小于CCR1_Val时为高电平(极性为正)
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;

反向端口到底是干嘛用的。。。

还有就是，为什么表里有128个点，但是半个周期采样100个，当然这样周期是可以保证50hz，但如果我把100改为127，周期是按照预想的所变化了，即（10KHZ/256=39.0HZ）但是波形确无法完美互补。。如图：

这个怎么破？

 

 

接下来上双极性的spwm：

程序部分，就是把死区给去掉了。

中断函数修改了其中的数组

void TIM4_IRQHandler(void)
{
 static vu16 sign = 0;
 static vu16 Counter_sine=0;
 static vu16 Duty_Cycle_sinewavetable[128]={
 3783,3952,4150,4320,4489,4658,4828,4997,5138,5308,
 5449,5618,5760,5901,6014,6155,6268,6381,6494,6607,
 6691,6776,6861,6917,7002,7058,7087,7143,7171,7171,
 7200,7200,7200,7171,7171,7143,7087,7058,7002,6917,
 6861,6776,6691,6607,6494,6381,6268,6155,6014,5901,
  5760,5618,5449,5308,5138,4997,4828,4658,4489,4320,
  4150,3952,3783,3614,3444,3275,3077,2908,2738,2569,
  2400,2230,2089,1920,1778,1609,1468,1327,1214,1072,
  960,847,734,621,536,451,367,310,225,169,141,84,56,56,
  28,28,28,56,56,84,141,169,225,310,367,451,536,621,734,
  847,960,1072,1214,1327,1468,1609,1778,1920,2089,2230,
  2400,2569,2738,2908,3077,3275,3444,3614
  };
 if ( TIM_GetITStatus(TIM4 , TIM_IT_Update) == SET)
 {
 
         TIM_SetCompare1(TIM3,Duty_Cycle_sinewavetable[Counter_sine]);
       
         Counter_sine++;
         if(Counter_sine==128)  //?????100??
         {
              Counter_sine=0;
         }
   }
 TIM_ClearITPendingBit(TIM4 , TIM_FLAG_Update);
}

注意这个数组是完整的正弦波了；关于数字的取得也想分享一下，作为菜鸟表示研究了好久。

因为自动装载值是7200，所以要以7200作为参考，如3600就是占空比为50%，然后用excel做表。大家不要笑话我哈，网上有正弦波生成表，用于单片机产生正弦波的，一般以256为最大比列，然后我就把生成的值除以256乘以7200得到上述数组。

注意，想要得到50hz的正弦波，就要使中断频率为50Hz*128=6400hz，根据公式反推 TIM_TimeBaseStructure.TIM_Period,TIM_TimeBaseStructure.TIM_Prescaler的值，也就是72M/(TIM_Period+1)*(TIM_Prescaler+1)=6400，

我就取

TIM_TimeBaseStructure.TIM_Period=4;          

TIM_TimeBaseStructure.TIM_Prescaler= 2249;