main.c

利用PWM产生高精度正弦波,从PWM引脚输出的脉冲信号经过简单的低通滤波后,可以得到平滑的正弦波,波的频率可以微调

//main.c
#include "ST7lib_config.h"
void main(void)
{
	unsigned  int  Conv_Data1,ii,jj;             
	                                                                          
	Nop;
	
	ARTARR = 0;
	
	PWMDCR0=0x20;
	PWMDCR1=0x40;
	PWMDCR2=0x80;
	PWMDCR3=0xc0;
	
	ARTCSR |=0x2f;
	PWMCR = 0xf5;
	_asm("RIM");
	while(1)
	{
		for(ii=0;ii<256;ii++)
		{
		     for(jj=0;jj<20;jj++)
		     Nop;			
		}
		PWMDCR1+=2;
		PWMDCR2+=3;
		PWMDCR3+=4;
	};              
	while(1);
	return;
}        


extern const int PWMDuty[];
static j;
@interrupt void PWMRefresh(void)
{
	static i;
	if(++i>=1)
	{	
		i=0;
		if(++j>100)
		j=0;
		PWMDCR0=PWMDuty[j];
	}
	ARTCSR&=0xfe;
}