[嵌入式]pwm控制led亮度 并且实现按键调档

?亮度分为三档? ?没按下一次按键? 档位会升高? 数码管显示相应的档位

#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit wela=P2^7;
sbit dula=P2^6;
sbit led1=P1^0;
sbit key1=P3^4;
uchar code table[]={
0x3f,0x06,0x5b,0x4f,
0x66,0x6d,0x7d,0x07,
0x7f,0x6f,0x77,0x7c,
0x39,0x5e,0x79,0x71};
//uchar code tablew[]=
//{0xfe,0xfd,0xfb,0xf7,0xef,0xdf};
void delay(uint z);
void display(uchar s);
void keysm();
uchar keynum,count,comprate;
void init()
{
		TMOD=0x01;
		TH0=(65536-1)/256;
		TL0=(65536-1)%256;
		EA=1;
		ET0=1;
		TR0=1;
}
void main()
{
		while(1)
		{															 
				 init();	
				 display(keynum);
         keysm();
			   switch(keynum)
				 {	 
					 case 0:
						 comprate=0;
						 break;
					 case 1:
						 comprate=5;
						 break;
					 case 2:
						 comprate=50;
					   break;
					 case 3:
						 comprate=100;
					   break;
				 }			
		}
}
void delay(uint z)   
{
		uint x,y;
		for(x=z;x>0;x--)
				for(y=110;y>0;y--);
}
void display(uchar s)
{		          		          	           							
		dula=1;
		P0=table[s];
		dula=0;
		P0=0xff;
		wela=1;
		P0=0xfe; 
		wela=0;
		delay(5);
}

void keysm()
{
		P3=0xff;
		while(1)
		{
				if(key1==0)
				{
						delay(5);
						if(key1==0)
						{
								keynum++;
								if(keynum==4)
								{
									keynum=0;
								}
								while(!key1);
								break;
								
						}
				}
		}
}
void time_0() interrupt 1
{
		TH0=(65536-1)/256;
		TL0=(65536-1)%256;
		count++;
		if(count==100)
		{
				count=0;
		}
		if(count<comprate)
		{
				
				led1=0;
		}
		else
		{   
				
				led1=1;
		}
		
}