新建 文本文档.c

来自「pwm改变占空比的程序」· C语言 代码 · 共 57 行

#include <reg52.h>

#define CIRCLE 20

void pwmkey(void);

unsigned char count=1,last;

sbit led=P1^0;
sbit key=P2^0;

void main(void)
{
	TMOD=0X01;
 EA=1;
 ET0=1;
 TH0=(65536-65516)/256;
 TL0=(65536-65516)%256;
 TR0=1;
 count=1;
 last=1;
 
 while(1)
 {
  pwmkey();
 }
}

void pwmkey(void)
{
 char old=0 ,new=0;
 while(1)
 {
  new=key;
  if(new && !old)
   last++;
  if(last>CIRCLE)
   last=1;
  old=new;
 }
}

void into(void) interrupt 1
{
 count++;
 if(count>CIRCLE)
 {
  count=1;
 }
 if(count<=last)
  led=0;
 else 
   led=1;
 TH0=(65536-65516)/256;
 TL0=(65536-65516)%256;
}