/*************************************************
程序名称：4x4矩阵键盘-数码显示键值
编译环境：CVAVR / 基于AVR
单 片 机：ATmega8515
实验对象：XY900_USB型学习开放系统板
月夜听风 http://www.mcusy.cn
*************************************************/
#include <mega8515.h>
#include <delay.h>
#define duan PORTD.3 //定义段选
#define wei   PORTD.4 //定义位选
unsigned char table[]=
{0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};
//--------------------------------------------------------
unsigned char Keyscan() //键盘扫描函数
{
       DDRB=0x0f; //高四位输入，低四位输出 00001111
       PORTB=0xfe; //11111110
       delay_ms(2);
       switch(PINB)
       {
               case 0xee:return 'D';
               case 0xde:return '#';
               case 0xbe:return 0 ;  
               case 0x7e:return '*';
               default:break;                
       }              
       PORTB=0xfd; //11111101
       delay_ms(2);
       switch(PINB)
       {
               case 0xed:return 'C';
               case 0xdd:return 9;
               case 0xbd:return 8;
               case 0x7d:return 7;
               default:break;                
       }              
       PORTB=0xfb; //11111011
       delay_ms(2);
       switch(PINB)
       {
               case 0xeb:return 'B';      
               case 0xdb:return 6;
               case 0xbb:return 5;
               case 0x7b:return 4;
               default:break;                
       }                    
       PORTB=0xf7;//11110111
       delay_ms(2);
       switch(PINB)
       {
               case 0xe7:return 'A';
               case 0xd7:return   3;
               case 0xb7:return   2;
               case 0x77:return   1;       ;
               default:break;                
       }
       return;
}

//--------------------------------------------------------
void display(unsigned char num)
{
       DDRD=0x18;
       DDRA=0xff;
       duan=1;PORTA=table[num];duan=0;//送显示段码
       delay_ms(2);   //
       wei=1;PORTA=0X40;wei=0; //开显示位码
       delay_ms(2);      
}
//--------------------------------------------------------
void main()
{
       unsigned char num;
       while(1)
       {
       num=Keyscan() ; //键值赋予num
       if(num>=0&&num<=9) //显示0~9
       display(num);
       }
}