#include <AT89X52.h>
#include "typedef.h"

#define Nothing 100
//端口定義
sbit C1 = P2^3;
sbit C2 = P2^4;
sbit C3 = P3^2;
sbit C4 = P3^3;

sbit R1 = P3^4;
sbit R2 = P3^5;
sbit R3 = P3^0;
sbit R4 = P3^1;

uchar Key=Nothing;		  //鍵盤緩沖寄存器（公有數據）
uchar Fn_Key;			 //功能鍵

//*********************************************************************
//= 函數原型: void KEYPAD_Scan(char* const Key, char* const Fn_Key)
//= 功    能: 掃描鍵盤
//= 參    數: 普通鍵New_Key，功能鍵New_FuncKey,緩存器的指針
//= 返 回 值:
//= 函數性質：私有函數
//**********************************************************************

void KEYPAD_Scan(char* const Key, char* const Fn_Key)
{

   C1 = 0; 
      if (R1 == 0) *Fn_Key = 'o'; //ON鍵
      if (R2 == 0) *Key    =  0;
      if (R3 == 0) *Fn_Key = '=';
      if (R4 == 0) *Key    = '+';
   C1 = 1;

   C2 = 0; 
      if (R1 == 0) *Key = 1;
      if (R2 == 0) *Key = 2;
      if (R3 == 0) *Key = 3;
      if (R4 == 0) *Key = '-';
   C2 = 1;

   C3 = 0; 
      if (R1 == 0) *Key = 4;
      if (R2 == 0) *Key = 5;
      if (R3 == 0) *Key = 6;
      if (R4 == 0) *Key = '*';
   C3 = 1;

   C4 = 0; 
      if (R1 == 0) *Key = 7;
      if (R2 == 0) *Key = 8;
      if (R3 == 0) *Key = 9;
      if (R4 == 0) *Key = '/';   

   C4 = 1;

}
//*********************************************************************
//= 函數原型: void KEY_Update()
//= 功    能: 鍵盤緩沖寄存器更新程序. 普通鍵Key, 功能鍵Fn_Key
//= 參    數: 
//= 返 回 值:
//= 函數性質：公有函數
//**********************************************************************
void KEY_Update() 
{
   static uchar delay=20;		//去抖動延時
   static bit delaying=0;		//標識是否正在延時

   if(delaying==0)
   {
       if(Key==Nothing)		   //如果Key緩存器中的數據未被讀取，則不掃描鍵盤
	   {
	      KEYPAD_Scan(&Key,&Fn_Key);	   //掃描鍵盤
		  if(Key!=Nothing)
		  {
		     delaying=1; 
			 Key=Nothing; 

		   }
		}
   }
   else
   {
      if(delay==0)				 //延時結束
	  {
	     KEYPAD_Scan(&Key,&Fn_Key);	   //讀取鍵盤
		 delay=20;
		 delaying=0;
	  }
	  else   delay--;			//延時減一
   }
}