如何利用ARM里的PWM模块产生SPWM波

        利用PWM模块产生SPWM波，主要是利用了PWM模块里一个比较器中断功能。通过比较器，产生一个中断，再附值产生一个PWM脉冲，一直循环，下去，通过附不同的值，就可以产生一个SPWM了。主要程序如下：     

const INT16U spwmwidth[spwmct]={24,72,120,168,215,262,308,353,398,441,484,525,565,604,641,677,
                     711,743,774,803,829,854,877,897,916,932,946,958,967,974,979,981,
                     981,979,974,967,958,946,932,916,897,877,854,829,803,774,743,711,
                     677,641,604,565,525,484,441,398,353,308,262,215,168,120,72,24
                                 };

void SpwmInit(void)
{     

    SysCtlPWMClockSet(SYSCTL_PWMDIV_64);                      // PWM时钟源64分频    
 
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);             // 使能PD口外设 
    
 SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM);               // 使能PWM外设  

 GPIOPinTypePWM(GPIO_PORTD_BASE, GPIO_PIN_0 | GPIO_PIN_1);// 设置PD0,PD1为PWM0和PWM1
  
    PWMGenConfigure(PWM_BASE, PWM_GEN_0,         // 设置PWM发生器0为上下计数方式，两路PWM不同步 
                    PWM_GEN_MODE_UP_DOWN | PWM_GEN_MODE_NO_SYNC | PWM_GEN_ACT_ZERO | PWM_GEN_ACT_ONE <<6);
                    //PWM0A 在计数器为0时，输出 为低电平，与比较器A值相等时输出为高电平 。 
 
 PWMOutputInvert(PWM_BASE, PWM_OUT_0_BIT | PWM_OUT_1_BIT,true);   //设置PWM两路反相

 PWMGenPeriodSet(PWM_BASE, PWM_GEN_0, 1000);             // 设置两路PWM的共同周期

    PWMDeadBandEnable(PWM_BASE,PWM_GEN_0,15,15);     //死区时间设置   
  
 PWMPulseWidthSet(PWM_BASE, PWM_OUT_0, spwmwidth[16]);            // 分别设置两路PWM的匹配值
  
   // PWMPulseWidthSet(PWM_BASE, PWM_OUT_1, 1000);
 
    PWMOutputState(PWM_BASE, PWM_OUT_0_BIT | PWM_OUT_1_BIT, true);// 使能PWM0和PWM1

 PWMGenEnable(PWM_BASE, PWM_GEN_0);                            // 使能PWM发生器0
 HWREG(PWM_BASE+0X044)|=0x01;
//    PWMGenIntRegister(PWM_BASE, PWM_GEN_0,*SpwmISRHandler) ;

     PWMIntEnable(PWM_BASE,PWM_INT_GEN_0);                //中断使能  WM发生器0模块    
     IntEnable(INT_PWM0);
}

#endif

/***********中断程序*****************************************************************************/
void  SpwmISRHandler (void)      
{
             
   static INT16U  count;
 
            #if OS_CRITICAL_METHOD == 3
                OS_CPU_SR cpu_sr;
            #endif

            OS_ENTER_CRITICAL();                       
            OSIntNesting++;
            OS_EXIT_CRITICAL();
     

   PWMGenIntClear(PWM_BASE, PWM_GEN_0,PWMIntStatus(PWM_BASE, true)|PWM_INT_GEN_0 );//清除中断 
   PWMPulseWidthSet(PWM_BASE, PWM_OUT_0, spwmwidth[count]);
   if (count>=63||count<=0 ){
                   count=1 ;
              }
             else {
                    count++;
              }

         OSIntExit();
}