/**********************************************
*   File: DirKeyboard_4.C
*   Description: Direct Keyboard Interface Example
*   Created Date:  2007-10-01
*   Last Modified: 2007-10-01
*   Author: Jeffrey - Schicksal@126.com
*   Notes: None
**********************************************/
#include <REGX51.h>

unsigned char Read_Keyboard();

/**********************************************
*   Function: delay(unsigned int t)
*   Input Variables: t
*   Return Variables: None
*   Usage: Common Delay Routine, t as the delay time ticks
**********************************************/
void delay(unsigned int t)
{
		for(;t>0;t--);		// 延時循環
}

/**********************************************
*   Function: main()
*   Input Variables: None
*   Return Variables: None
*   Usage: Program Entry
*********************************************/
void main()
{
		unsigned char LED_Status = 0xff;									// 定義鍵值
		unsigned char Keyboard_OLD = 0xff;
		unsigned char Keyboard_Status[5] = {0xff,0xff,0xff,0xff,0xff};		// 定義鍵值
		unsigned char jTemp;												// 臨時變量
		unsigned char iTemp;												// 臨時變量
		unsigned char BStatus;
		while(1)
		{
			for(iTemp=0;iTemp<5;iTemp++)
			{
				Keyboard_Status[iTemp] = Read_Keyboard();	 //連續5次讀取按鍵值
			}
			BStatus = Keyboard_Status[0]| \
					  Keyboard_Status[1]| \
					  Keyboard_Status[2]| \
					  Keyboard_Status[3]| \
					  Keyboard_Status[4];					 // 處理0值
				for(iTemp = 1;iTemp<129;iTemp<<1) 			 // 掃描狀態位	
				{
					if(iTemp&Keyboard&(~BStatus))  			 // 按鍵被按下一次
					{
							LED_Status ^= iTemp; 	  		 // Toggle LED
					}
				}
			Keyboard_OLD &= BStatus;						 // 存儲狀態
			BStatus = Keyboard_Status[0]& \
					  Keyboard_Status[1]& \
					  Keyboard_Status[2]& \
					  Keyboard_Status[3]& \
					  Keyboard_Status[4]; 					 // 處理1值
			Keyboard_OLD |= BStatus;						 // 存儲狀態
			P0 = ~LED_Status;								 // 點亮相應的LED燈				
			//********************主程序部分*********************//
			// Add your code here
			//********************主程序部分*********************//
		}
}
	
/**********************************************
*   Function: Read_Keyboard
*   Input Variables: None
*   Return Variables: Keys Value
*   Usage: Read Keyboard Status
*********************************************/
unsigned char Read_Keyboard()
{
		unsigned char Keys_Value;					 // 定義鍵值變量
		P2 = 0xff;									 // P2口置高，準備讀取按鍵狀態
		Keys_Value = P2;							 // 讀取按鍵狀態
		return Keys_Value;							 // 返回按鍵狀態值
}