/*實驗名稱：按加減鍵實現內部加減 0.01
  功能：數碼顯示0.20---2.00
  作者：http://www.mcuprog.com
        05-02-01
*/
#include <reg51.h>
//LCD的口線
sbit E=P3^5;
sbit RW=P3^6;
sbit RS=P3^7;	
unsigned char dpbl,ledbai,ledshi,ledge,keytime;
unsigned char bdata myflag;
sbit keybit = myflag^0;

void time0(void);
void keyscan(void);
void Delay(unsigned int t);
void SendCommandByte(unsigned char ch);
void SendDataByte(unsigned char ch);
void InitLcd(void);
void dispdpbl(void);

void main(void)
{
	InitLcd();
	myflag=0x00;
	dpbl=20;
	keytime=4;		//20MS掃一次按鍵
	SendCommandByte(0x80);
	Delay(2);
	SendDataByte('S');
	SendDataByte('U');
	SendDataByte('M');
	SendDataByte(':');
	TH0=0xee;		//定時5MS
	TL0=0x00;
	TMOD=0x01;
	TR0=1;
	IE=0x82;
	while(1)
	{}	
}	

void time0(void) interrupt 1
{
	TH0=0xee;
	TL0=0x00;
	if(keytime--==0)
	{keytime=0x04;P1=0xff;keyscan();
	ledbai=(dpbl/100)|0x30;
	ledshi=((dpbl%100)/10)|0x30;
	ledge=(dpbl%10)|0x30;
	dispdpbl();
	}
}  

void keyscan(void)
{
	if(P1==0xfe)
	{
		if(keybit==0)
		{keybit=1;dpbl++;if(dpbl>200){dpbl=20;}}
	}
	else
	{
		if(P1==0xfd)
		{
			if(keybit==0)
			{keybit=1;dpbl--;if(dpbl<20){dpbl=200;}}
		}
		else
		{
			if(P1==0xff){keybit=0;}
		}
	}
	P1=0xff;
}

void Delay(unsigned int t)   // delay 40us
{
 for(;t!=0;t--) ;
}
//=============================================
void SendCommandByte(unsigned char ch)
{
   RS=0;
   RW=0;
   P0=ch;
   E=1;
    Delay(1);
   E=0;
   Delay(100);  //delay 40us
}
//-------------------------------------------------------
void SendDataByte(unsigned char ch)
{  RS=1;
   RW=0;
   P0=ch;
   E=1;
       Delay(1);
   E=0;
   Delay(100); //delay 40us
}
//-------------------------------------------------
void InitLcd(void)
{SendCommandByte(0x30);
 SendCommandByte(0x30);
 SendCommandByte(0x30);
 SendCommandByte(0x38);	//設置工作方式
 SendCommandByte(0x0c); //顯示狀態設置
 SendCommandByte(0x01); //清屏
 SendCommandByte(0x06); //輸入方式設置
}

void dispdpbl(void)
{
	SendCommandByte(0x85);
	SendDataByte(ledbai);
	SendDataByte('.');
	SendDataByte(ledshi);
	SendDataByte(ledge);
	
}