實現(xiàn)LED分級亮度的簡便算法

#include"reg52.h"
unsigned char code table[]={0xfe,0xfc,0xf0,0xe0,0xc0,0x80,0x00};
void main()
{
  unsigned char i;
  while(1)
   {
     i++;
     i&=0x07;
     P1=table;
    }
}

低電平點亮LED，i=0到7；
while循環(huán)周期*8=PWM的周期
當i=0時，D0亮
當i=1時，D0,D1亮
當i=2時，D0,D1,D2亮
。。。。。。
當i=7時，D0,D1,D2,D3,D4,D5,D6,D7全亮
也就是說，在while的8個循環(huán)中，D0一直亮，D1則只有7次亮。。。。。。D7則只有1次亮

按照這個算法，只要定義一個一維表格，就可以靜態(tài)現(xiàn)實LED的8個不同亮度，且亮度次序任意
如果定義一個二維表格，則可以動態(tài)現(xiàn)實LED亮度，幾乎可以任意定義次序花樣

下面來看一個完整的二維數(shù)組漸變程序
完整代碼下載地址：http://www.torrancerestoration.com/f/jianb.rar

#include "reg52.h" 
unsigned char code table[37][8]=   //定義一個2維數(shù)組 
{0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,//off 
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xfe,//D0亮度等級1/8 
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xfc,//D1亮度等級1/8 
0xff,0xff,0xff,0xff,0xff,0xff,0xfd,0xfc,//D1亮度等級2/8 
0xff,0xff,0xff,0xff,0xff,0xff,0xfd,0xf8,//D2亮度等級1/8 
0xff,0xff,0xff,0xff,0xff,0xff,0xf9,0xf8,//D2亮度等級2/8 
0xff,0xff,0xff,0xff,0xff,0xfb,0xf9,0xf8,//D2亮度等級3/8 
0xff,0xff,0xff,0xff,0xff,0xfb,0xf9,0xf0,//D3 
0xff,0xff,0xff,0xff,0xff,0xfb,0xf1,0xf0, 
0xff,0xff,0xff,0xff,0xff,0xf3,0xf1,0xf0, 
0xff,0xff,0xff,0xff,0xf7,0xf3,0xf1,0xf0, 
0xff,0xff,0xff,0xff,0xf7,0xf3,0xf1,0xe0,//D4 
0xff,0xff,0xff,0xff,0xf7,0xf3,0xe1,0xe0, 
0xff,0xff,0xff,0xff,0xf7,0xe3,0xe1,0xe0, 
0xff,0xff,0xff,0xff,0xe7,0xe3,0xe1,0xe0, 
0xff,0xff,0xff,0xef,0xe7,0xe3,0xe1,0xe0, 
0xff,0xff,0xff,0xef,0xe7,0xe3,0xe1,0xc0,//D5 
0xff,0xff,0xff,0xef,0xe7,0xe3,0xc1,0xc0, 
0xff,0xff,0xff,0xef,0xe7,0xc3,0xc1,0xc0, 
0xff,0xff,0xff,0xef,0xc7,0xc3,0xc1,0xc0, 
0xff,0xff,0xff,0xcf,0xc7,0xc3,0xc1,0xc0, 
0xff,0xff,0xdf,0xcf,0xc7,0xc3,0xc1,0xc0, 
0xff,0xff,0xdf,0xcf,0xe7,0xe3,0xc1,0x80,//D6 
0xff,0xff,0xdf,0xcf,0xe7,0xe3,0x81,0x80, 
0xff,0xff,0xdf,0xcf,0xe7,0x83,0x81,0x80, 
0xff,0xff,0xdf,0xcf,0x87,0x83,0x81,0x80, 
0xff,0xff,0xdf,0x8f,0x87,0x83,0x81,0x80, 
0xff,0xff,0x9f,0x8f,0x87,0x83,0x81,0x80, 
0xff,0xbf,0x9f,0x8f,0x87,0x83,0x81,0x80, 
0xff,0xbf,0x9f,0x8f,0x87,0x83,0x81,0x00,//D7 
0xff,0xbf,0x9f,0x8f,0x87,0x83,0x01,0x00, 
0xff,0xbf,0x9f,0x8f,0x87,0x03,0x01,0x00, 
0xff,0xbf,0x9f,0x8f,0x07,0x03,0x01,0x00, 
0xff,0xbf,0x9f,0x0f,0x07,0x03,0x01,0x00, 
0xff,0xbf,0x1f,0x0f,0x07,0x03,0x01,0x00, 
0xff,0x3f,0x1f,0x0f,0x07,0x03,0x01,0x00, 
0x7f,0x3f,0x1f,0x0f,0x07,0x03,0x01,0x00, 
}; 

void main()         
{ 
unsigned char i; 
unsigned int j; 
unsigned int counter; 
bit flag=0; 
while(1) 
{ 
  i++; 
  i&=0x07;       //i=0到7 
  counter++; 
  if(counter==12000)     //延時對j++ 
  { 
   if(flag==0) j++;     
   else j--; 
   counter=0; 
   if(j==36 || j==0) 
   { 
    flag=!flag;     //決定正向掃描還是逆向掃描 
    i=0; 
   } 
  } 
   P1=table[j];     //掃描第i列，掃描第j行 
} 
} 

注意：用2003時，是高電平點亮LED。要對它取反。