51单片机电子时钟C语言程序

51最基础简单易懂的单片机，差不多一个月的时间，断断续续地学习，终于算是学完了，下个目标是飞思卡尔s12x和k60 也就是 crotex-M4架构. 51最核心的部分，我觉得是中断的使用，一个项目离不开中断，还有就是串口的理解，还有就是IIC通信。
以 电子时钟 为结尾篇，附上代码。代码有些不怎么完美。但终究是差不多写出来了。结合了IIC通信，中断定时器的使用，使用，还有液晶的显示。

#include  sbit RS = P2^7;sbit RW = P2^6;sbit E = P2^5;sbit Sda = P2^0;sbit Scl = P2^1;sbit keyleft = P1^0;sbit keyup = P1^1;sbit keydown = P1^2;sbit keyright = P1^3;unsigned char sec=0,min=0,hour=0;unsigned char Year[20]="   2012.10.1   ";unsigned char i;unsigned int times = 0;unsigned char countleft = 0,countright = 0;unsigned char busycheck();static void Start(void){	Sda = 1;	Scl = 1;	Sda = 0;}static void Stop(void){	Sda = 0;	Scl = 1;	Sda = 1;}static unsigned char Respons(void){	unsigned char OverTime = 0;  //超时	unsigned char TempFlag = 0;	OverTime = 0;    Sda = 1;     //释放数据线    Scl = 1;	while(1)	{		if(Sda)   //应答信号没来		{			if(OverTime++ > 200)			{			  TempFlag = 0;   //应答信号长时间没有来，认为无应答			  break;			}		}		else		{		   TempFlag = 1;    ///检测到应答信号			break;		}	}	Scl = 0;	return TempFlag;}static void NoRespons(void)  //非应答{    Sda = 1;     //释放数据线    Scl = 1;	Scl = 0;}static void WriteByte(unsigned char temp){	unsigned char i;	Scl = 0;	for(i = 0;i < 8;i++)	{		Sda = temp & 0x80;		temp <<= 1;		Scl = 1;    //scl拉高，准备写数据		Scl = 0;   //scl拉低，写数据完成	}}static unsigned char ReadByte(void){	unsigned char i;	unsigned char x = 0;	for(i = 0;i < 8;i++)	{		Scl = 1;		x <<= 1;		x |= (unsigned char)Sda;		Scl = 0;		}	return x;}void WriteIIC(unsigned char device,unsigned char parameter,unsigned char temp){	Start();	WriteByte(device);	if(Respons())	{		WriteByte(parameter);		if(Respons())		{			WriteByte(temp);			if(Respons())			{				Stop();			}			else			{				Stop();			}		}		else		{			Stop();		}	}	else	{		Stop();	}}unsigned char ReadIIC(unsigned char device,unsigned char parameter){	unsigned char x;	Start();	WriteByte(device);	if(Respons())	{		WriteByte(parameter);		if(Respons())		{			Start();			WriteByte(device | 0x01);			if(Respons())			{				x = ReadByte();				NoRespons();				Stop();			}			else			{				Stop();			}		}		else		{			Stop();		}	}	else	{		Stop();	}	return x;}void writecmd(unsigned char cmd){	while(busycheck());	RS = 0;	RW = 0;	E = 1;	P0 = cmd;	E = 0;}void writedata(unsigned char dat){	while(busycheck());	RS = 1;	RW = 0;	E = 1;	P0 = dat;	E = 0;}unsigned char busycheck(){	P0 = 0xff;	RS = 0;	RW = 1;	E = 0;	E = 1;	return(P0 & 0x80);}void writedate(unsigned char add,unsigned char date){	unsigned char shi,ge;	shi = date/10;	ge = date%10;	writecmd(0x80+0x40+add);	writedata(0x30+shi);	writedata(0x30+ge);}void Init(){		writecmd(0x38);//显示模式        writecmd(0x08);//关屏        writecmd(0x01);//清屏        writecmd(0x06);//设置光标右移	writecmd(0x0c);//显示，无标 闪烁	writecmd(0x80);	for(i = 0;i < 20;i++)		writedata(Year[i]);	writecmd(0x80+0x40+6);	writedata(':');	writecmd(0x80+0x40+9);	writedata(':');	sec = ReadIIC(0xa0,0);	min = ReadIIC(0xa0,2);	hour = ReadIIC(0xa0,4);	writedate(10,sec);	writedate(7,min);	writedate(4,hour);	TMOD = 0x02;	TH0 = 6;	TL0 = 6;	EA = 1;	ET0 = 1;	TR0 = 1;}void delay(){	unsigned char x = 2000;	while(x--);}void keyscan(){	if(!keyleft)	{		delay();		if(!keyleft)		{			TR0 = 0;			if(countleft == 0)			{				countleft++;				writecmd(0x80+0x40+10);				writecmd(0x0f);			}			else				if(countleft == 1)				{					countleft++;					writecmd(0x80+0x40+7);				}				else					if(countleft == 2)					{					countleft++;					writecmd(0x80+0x40+4);					}					else						if(countleft == 3)						{							TR0 = 1;							writecmd(0x0c);							countleft = 0;						}						else						{						}		 			}		else		{		}	}	else	{	}	if(!keydown)	{		delay();		if(!keydown)		{			if(countleft == 1)			{				sec--;				if(sec == 60)					sec = 0;				writedate(10,sec);				WriteIIC(0xa0,1,sec);				writecmd(0x80+0x40+10);			}			else				if(countleft == 2)				{					min--;					if(min == 60)						min = 0;					writedate(7,min);					WriteIIC(0xa0,2,min);					writecmd(0x80+0x40+7);				}				else					if(countleft == 2)					{						hour--;						if(hour == 24)							hour = 0;						writedate(4,hour);						WriteIIC(0xa0,3,hour);						writecmd(0x80+0x40+4);					}					else					{					}		 			}		else		{		}	}	else	{	}	if(!keyright)	{		delay();		if(!keyright)		{			if(countleft == 1)			{				sec++;				if(sec == 60)					sec = 0;				writedate(10,sec);				writecmd(0x80+0x40+10);			}			else				if(countleft == 2)				{					min++;					if(min == 60)						min = 0;					writedate(7,min);					writecmd(0x80+0x40+7);				}				else					if(countleft == 2)					{						hour++;						if(hour == 24)							hour = 0;						writedate(4,hour);						writecmd(0x80+0x40+4);					}					else					{					}		 			}		else		{		}	}	else	{	}}void main(){	Init();	while(1)	{		keyscan();	}}void Time0(void) interrupt 1{	times++;	if(times == 3686)		{			times = 0;			sec++;			if(sec == 60)			{				sec = 0;				min++;				if(min == 60)				{					min = 0;					hour++;					if(hour == 24)					{						hour = 0;					}					writedate(4,hour);					WriteIIC(0xa0,3,hour);				}				writedate(7,min);				WriteIIC(0xa0,2,min);			}			writedate(10,sec);			WriteIIC(0xa0,1,sec);		}} 

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