单片机PWM LED渐变时间怎么调

ID:109460 · 发表于 2016-3-19 08:40

#include<reg52.h>
//#include "MacroAndConst.h"
#define uint unsigned int
#define uchar unsigned char
#define LED_PWM_LIMIT_MAX 9999
#define LED_PWM_LIMIT_MIN 0
#define uchar unsigned char
sbit ledr=P1^0;
sbit ledg=P1^1;
sbit ledb=P1^2;
bit LEDDirection=0;//LED控制方向0：渐亮1：渐灭
uchar pwm=0;
uchar pwmr=0;
uchar scw=0;//中断记数
void Timer0Init(void)
{
  TMOD=0x01;
  TH0=0xff;
  TL0=0x47;
  ET0=1;
  TR0=1;
  EA=1;
}
void main()
{
  Timer0Init();
  while(1);

}
void Time0Isr(void) interrupt 1
{  static uint
   pwm=0;
   TH0=0xff;
   TL0=0x47;
scw++;
  if(scw>100)
  {
scw=0;
if((pwmr<=LED_PWM_LIMIT_MAX)&&(0==LEDDirection))
   {
      pwmr++;
   if(pwmr>LED_PWM_LIMIT_MAX)
   {
      LEDDirection=1;
      pwmr=LED_PWM_LIMIT_MAX;
   }

   }
   if((pwmr>=LED_PWM_LIMIT_MIN )&&(1==LEDDirection))
      {
               pwmr--;
            if(pwmr<LED_PWM_LIMIT_MIN )
            {
               LEDDirection=0;
               pwmr=LED_PWM_LIMIT_MIN ;
            }

      }
         pwm=pwmr;

  }

      if(pwm>0)
         {
            ledr=0;
            pwm--;
         }
         else
         {
            ledr=1;
         }
}
怎么调max值整体时间却不变

ID:106431 · 发表于 2016-3-19 09:39

楼主分享的代码好齐全啊

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