PIC16F877矩阵键盘的识别

原文地址：http://blog.sina.com.cn/s/blog_4a3946360100mwqh.html

关于矩阵键盘的识别方法在51矩阵键盘识别中已经说过，现在要说的是PIC单片机与51单片机的区别，主要是PIC单片机的口子的输入输出需要TRISn寄存器设置，具体如下：

扫描法：

#include<pic.h>
#define uchar unsigned char
#define uint unsigned int
uchar num;
const ucharSSEG[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};

void delay1ms(uint z)
{
 uint x;
 uchar y;
 for(x=z;x>0;x--)
  for(y=110;y>0;y--);
}

void keyscan()
{
 uchar temp;
 TRISB=0x0f;
 PORTB=0x7f;
 temp=PORTB&0x0f;
 if(temp!=0x0f)
 {
  delay1ms(10);
  temp=PORTB&0x0f;
  if(temp!=0x0f)
  {
   num=temp|0x70; 
  }
  temp=PORTB&0x0f;
  while(temp!=0x0f)
  {
   temp=PORTB&0x0f;  
  }
  switch(num)
  {
   case 0x7e:num =12;break;
    case0x7d: num =13;break;
   case 0x7b:num =14;break;
   case 0x77:num =15;break;
  }
 }
 PORTB=0xbf;
 temp=PORTB&0x0f;
 if(temp!=0x0f)
 {
  delay1ms(10);
  temp=PORTB&0x0f;
  if(temp!=0x0f)
  {
   num=temp|0xb0; 
  }
  temp=PORTB&0x0f;
  while(temp!=0x0f)
  {
   temp=PORTB&0x0f;  
  }
  switch(num)
  {
   case 0xbe:num =8;break;
    case0xbd: num =9;break;
   case 0xbb:num =10;break;
   case 0xb7:num =11;break;
  }
 }
 PORTB=0xdf;
 temp=PORTB&0x0f;
 if(temp!=0x0f)
 {
  delay1ms(10);
  temp=PORTB&0x0f;
  if(temp!=0x0f)
  {
   num=temp|0xd0; 
  }
  temp=PORTB&0x0f;
  while(temp!=0x0f)
  {
   temp=PORTB&0x0f;  
  }
  switch(num)
  {
   case 0xde:num =4;break;
    case0xdd: num =5;break;
   case 0xdb:num =6;break;
   case 0xd7:num =7;break;
  }
 }
 PORTB=0xef;
 temp=PORTB&0x0f;
 if(temp!=0x0f)
 {
  delay1ms(10);
  temp=PORTB&0x0f;
  if(temp!=0x0f)
  {
   num=temp|0xe0; 
  }
  temp=PORTB&0x0f;
  while(temp!=0x0f)
  {
   temp=PORTB&0x0f;  
  }
  switch(num)
  {
   case 0xee:num =0;break;
    case0xed: num =1;break;
   case 0xeb:num =2;break;
   case 0xe7:num =3;break;
  }
 }      
}

void main()
{
 num=0xff;
 TRISD=0;
 PORTD=0;
 while(1)
 {
  keyscan();
  PORTD=~SSEG[num];
 }
}

线反转法：

#include<pic.h>
#define uchar unsigned char
#define uint unsigned int
uchar num;
const ucharSSEG[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};

void delay1ms(uint z)
{
 uint x;
 uchar y;
 for(x=z;x>0;x--)
  for(y=110;y>0;y--);
}

void keyscan()
{
 uchar temp,z,x;
 TRISB=0x0f;
 PORTB=0x0f;
 x=PORTB&0x0f;
 if(x!=0x0f)
 {
  delay1ms(10);
  x=PORTB&0x0f;
  if(x!=0x0f)
  {
   temp=PORTB&0x0f;
   TRISB=0xf0;
   PORTB=0xf0;  
   z=temp|PORTB;
   x=PORTB&0xf0;
   while(x!=0xf0)//松手检测
   {
    x=PORTB&0xf0;  
   }
   switch(z)
   {
    case0xee: num =0; break;
         case 0xde: num =4; break;
         case 0xbe: num =8; break;
         case 0x7e: num =12; break;
         case 0xed: num =1; break;
         case 0xdd: num =5; break;
         case 0xbd: num =9; break;
         case 0x7d: num =13; break;
         case 0xeb: num =2; break;
         case 0xdb: num =6;break;    
         case 0xbb: num =10;break;
         case 0x7b: num =14;break;
         case 0xe7: num =3;break;
         case 0xd7: num =7;break;
         case 0xb7: num =11;break;
         case 0x77: num =15;break;
   }
  }
 }
}

void main()
{

 

num=0xff;
 TRISD=0;
 PORTD=0;
 while(1)
 {
  keyscan();
  PORTD=~SSEG[num];
 }
}