今天用STM8s試了下調(diào)制SPWM,查表法做的，定時(shí)器1通道2引腳輸出SPWM，又通過(guò)一個(gè)LC濾波，就看到了下面的正弦波

#include "IOSTM8S103K3.h"
#include "math.h"
#include 
#define LED PC_ODR_ODR2

unsigned int pwm_duty[100];



unsigned char j=0; /* Phase difference */

unsigned char cnt_pwm=0;

void math(void)
{  
   unsigned char i;
   for(i=0; i<100; i++)
    {

       pwm_duty[i]=(unsigned int)(127+(float)127*sin(2*3.1415926*(float)i*0.2/(float)20));
   
    } 
}
void delay_us(unsigned int us)
{
       unsigned char j;
       while(us!=0)
       {
              for(j=0;j<250;j++)
              {}
              us--;
       }
} 

void Init_Timer4(void)
{  
    asm("sim"); 
    TIM4_CR1=0x01;//使能計(jì)數(shù)器
    TIM4_IER=0x01;//更新中斷使能
    TIM4_EGR=0x01;
    TIM4_CNTR=199;//計(jì)數(shù)器值
    TIM4_ARR=199;//自動(dòng)重裝的值
    TIM4_PSCR=0x02;//分頻值128
    asm("rim");//開(kāi)全局中斷，延時(shí)16.32ms
}
#pragma vector=TIM4_OVR_UIF_vector//0x19
__interrupt void TIM4_OVR_UIF_IRQHandler(void)//對(duì)應(yīng)IAP的中斷地址：0x8060
{
   TIM4_SR=0x00;
   cnt_pwm++;


   
  
    if (cnt_pwm>3)
    {
      cnt_pwm=0;  
      /* Sin wave CC1 PB0*/
   

      if(j>= 100) j=0;
      TIM1_CCR2H = (unsigned char)(pwm_duty[j]>>8);
      TIM1_CCR2L = (unsigned char)(pwm_duty[j]&0x00ff);
      j++;


    }


}
void TIM1_CH2_PWM_INIT(void)
 {
  CLK_PCKENR1|=0x80;//開(kāi)啟定時(shí)器1外設(shè)時(shí)鐘 
  TIM1_EGR=0x01;//重新初始化TIM1
  TIM1_EGR|=0x60;//重新初始化TIM1
  TIM1_ARRH=0x00;//設(shè)定重裝載值
  TIM1_ARRL=255;
  TIM1_PSCRH=0;//預(yù)分頻
  TIM1_PSCRL=1;
  TIM1_CR1=0;//邊沿對(duì)齊,向上計(jì)數(shù)
  
  TIM1_CCER1=0x11;//高電平有效
  
  TIM1_CCMR1=0x60;//PWM模式1
   TIM1_CCMR2=0x60;//PWM模式1
  
  TIM1_CCR2H=0;//占空比
  
  TIM1_CCR2L=254;
    
  TIM1_CCR1H=0;//占空比
  
  TIM1_CCR1L=254;
  
  TIM1_CR1|=0x01;//向上計(jì)數(shù)，無(wú)緩存，使能
  TIM1_BKR=0x80;//開(kāi)啟剎車
 }
void main( void )
{


    /*High speed internal clock prescaler: 1*/
          CLK_CKDIVR = 0x00;
          math();
          PC_DDR|=0x04;
	  PC_CR1|=0x04;
	  PC_CR2|=0x00;
          Init_Timer4();
          TIM1_CH2_PWM_INIT();





 


    while(1)
  {   
}


}