#include <reg51.h>
#include "PS2.H"

BYTE PS2RecChar=0xCC;
BOOL KeyBoardFlag=FALSE;

void OnKeyBoardOnline(BOOL i)
{
	KeyBoardFlag=i;
}	
//---------------------------------------------------------------------------
void OnPS2ReceiveChar(BYTE ReceChar,BOOL P)
{
	BOOL ParityBit=0;
	ACC=ReceChar;
	CY=P;
	ParityBit=(BOOL)(CY?0x00:0x80);//奇校驗位
	if(P==ParityBit);
	PS2RecChar=ReceChar;
}
//---------------------------------------------------------------------------
void OnPS2SendChar(BYTE dat)
{
	BOOL ParityBit;
	BYTE i;
	ACC=dat;
	CY=P;
	ParityBit=(BOOL)(CY?0x00:0x80);//奇校驗位
	
	CLSSIGNAL();

	CT_KB=OFF;
	EX0=0;

	H_DATA=0;Delay10us();//start bit
	H_CLK=1;
	Delay10us();
	H_CLK=0;
	Delay30us();
	
	for(i=0;i<8;i++)
	{
		if(dat&0x01==0x01){H_DATA=1;Delay10us();}
		else {H_DATA=0;Delay10us();}
		dat>>=1;
		H_CLK=1;
		Delay10us();
		H_CLK=0;
		Delay30us();
	}

	H_DATA=ParityBit;Delay10us();//parity bit
	H_CLK=1;
	Delay10us();
	H_CLK=0;
	Delay30us();

	H_DATA=1;Delay10us();//stop bit
	H_CLK=1;
	Delay10us();
	H_CLK=0;
	Delay30us();
	
	IE0=0;
	EX0=1;
	H_CLK=1;
	H_DATA=1;
	CT_KB=ON;
	Delay30us();
}
//---------------------------------------------------------------------------
void ExternInterrupt0(void) interrupt 0
{
	BOOL ParityBit=0,CLKFlag=1;
	BYTE i=0,j=8,dat=0x00;

	EX0=0;

	while(CLKFlag)
	{
		i++;
		if(H_CLK==1)CLKFlag=0;
		if(i>0xEE)
		{
			IE0=0;
			EX0=1;
			return ;
		}
	} 
	while(j--)//延時等待大鍵盤的動作
	{
		for(i=0;i<0x88;i++)//檢查是否有數據處理	0x88
		{
			if(H_CLK==0)//有動作則是大鍵盤存在
			{
				OnKeyBoardOnline(TRUE);//大鍵盤存在,開機由大鍵盤應答
				IE0=0;
				EX0=1;
				return ;//存在的話置標志位，并返回
			}
		}
	}
	OnKeyBoardOnline(FALSE);//大鍵盤不存在，由小鍵盤應答
	
	//轉到接收
	for(i=0;i<8;i++)//read 8bit
	{
		Delay30us();
		H_CLK=0;            
		Delay30us();
		H_CLK=1;
		dat=dat>>1;    
		if(H_DATA)dat|=0x80;
		
		if(H_CLK==0){	return;	}//如果時鐘被拉低，則有錯誤發生
	}
										 
	Delay30us();
	H_CLK=0;            
	Delay30us();
	H_CLK=1;
	if(H_DATA)ParityBit=1;
	else ParityBit=0; 

	Delay30us();
	H_CLK=0;            
	Delay30us();
	H_CLK=1;//STOP BIT H_DATA 0 ERR
	
	Delay10us();
	H_DATA=0;	//ACK bit
	Delay10us();
	H_CLK=0;
	Delay30us();Delay30us();
	H_CLK=1;
	Delay30us();
	H_DATA=1;
	
	OnPS2ReceiveChar(dat,ParityBit);

	IE0=0;
	EX0=1;
	return ;
}
//---------------------------------------------------------------------------
void ProcessPS2(void)
{
	if(KeyBoardFlag==FALSE)//大鍵盤不存在
	{
		if(PS2RecChar==0xF3)//1
		{
			OnPS2SendChar(0xFA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0x00)//11
		{
			OnPS2SendChar(0xFA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0x02)//111
		{
			OnPS2SendChar(0xFA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0x20)//1111
		{
			OnPS2SendChar(0xFA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xED)//2
		{
			OnPS2SendChar(0xFA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xF0)//3
		{
			OnPS2SendChar(0xFA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xF2)//4
		{
			OnPS2SendChar(0xFA);
			Delay30us();
			OnPS2SendChar(0xAB);
			Delay30us();
			OnPS2SendChar(0x83);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xEF)//5
		{
			OnPS2SendChar(0xFA);
			Delay30us();
			OnPS2SendChar(0xBF);
			Delay30us();
			OnPS2SendChar(0xB0);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xF3)//6
		{
			OnPS2SendChar(0xFA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xFE)//7 //resend
		{
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xEE)//8
		{
			OnPS2SendChar(0xEE);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xEE)//9
		{
			OnPS2SendChar(0xEE);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xF1)//10
		{
			OnPS2SendChar(0xFA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xF4)//11
		{
			OnPS2SendChar(0xFA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xAA)//12
		{
			OnPS2SendChar(0xAA);
			PS2RecChar=0xCC;
		}
		else if(PS2RecChar==0xFF)//13
		{
			OnPS2SendChar(0xFA);
			Delay30us();
			OnPS2SendChar(0xAA);
			Delay30us();
			PS2RecChar=0xCC;
		}
		else ; 
	}
}
//---------------------------------------------------------------------------
void PS2Init(void)
{
	IT0=0;	//低電平觸發中斷
	PX0=1;	
	EX0=1;	
}
//---------------------------------------------------------------------------
/*
//用法-以下文件在main.c--------------------------------------------------------------------------
//把PS2.C Delay.asm加入工程
extern void ProcessPS2(void);
extern void PS2Init(void)
void main(void)
{
	//晶振為18.432 其他的頻率需要修改延時程序
	//往PC上發按鍵使用OnPS2SendChar（）；
	//OnPS2SendChar(0x15);//Q//發送通碼

	//OnPS2SendChar(0xF0);
	//OnPS2SendChar(0x15);//Q//發送斷碼
	PS2Init();
	while(1)
	{
		ProcessPS2();//開機應答,使電腦能識別到鍵盤
		//other code
	}
}

 */