//文件名：	WRS485R.c 程序用UART1外擴(kuò)MAX485實(shí)現(xiàn)RS-485通信，運(yùn)行前將TX1和P00 短//接，RX1和P01短接，當(dāng)接收到一個(gè)數(shù)據(jù)后，再將接收到的數(shù)據(jù)送出。
#include <c8051f020.h>                 /*SFR定義*/
#include <intrins.h>
#define SYSCLK       11059200          /*系統(tǒng)頻率*/
#define BAUDRATE     9600              /*波特率*/
sbit	BUZ = P3^5;
sbit	P32 = P3^2;						/*接收/發(fā)送控制*/
void SYSCLK_Init (void);
void PORT_Init (void);
void UART1_Init (void);
void UART1_ISR (void);
void LCD_Init(void);
bit	ReceiveBit;
unsigned char temp;
float  FFF;	
int    ff;
/*延時(shí)子程序*/
void delay(unsigned int m)
{
	unsigned int n;
	n=0;
	while(n < m)
	{n++;}
	return;
}

void main (void) {
    WDTCN = 0xde;                       /*關(guān)看門狗*/
   WDTCN = 0xad;
   ReceiveBit=0;
   SYSCLK_Init ();                     /*初始化系統(tǒng)時(shí)鐘*/
   PORT_Init ();                       /*初始化I/O口*/
   LCD_Init();
   UART1_Init ();                      /*初始化UART1*/
   EA = 1;                             /*開總中斷*/
   EIE2  |= 0x40;                      /*UART1中斷*/
   P32 = 0;								/*接收模式*/
    P7 = 0x52;                          /*顯示R>*/
	P6 = 0x0c;
	P6 = 0x0d;
	delay(300);				    /*延時(shí)*/
	P7 = 0x3e; 
	P6 = 0x0c;
	P6 = 0x0d;
	while(1){
		while (ReceiveBit==1) {			/*接收到一個(gè)數(shù)據(jù)*/
			ReceiveBit=0;				/*清接收位*/
			if(temp==0)break;           /*如果接收的是空則不顯示*/
			P7 = temp;                  /*顯示接收字符*/
			P6 = 0x0c;
	        P6 = 0x0d;		
		}
		 nop ();
	}
}
void SYSCLK_Init (void)
{
   int i;                              /*延時(shí)計(jì)數(shù)器*/
   OSCXCN = 0x67;                      /*開始外部22.1184MHz晶體*/
   for (i=0; i < 256; i++) ;           /*等待外部晶體起振穩(wěn)定*/
   while (!(OSCXCN & 0x80)) ;          /*查詢標(biāo)志位*/
   OSCICN = 0x88;                      /*用外部晶體頻率作為系統(tǒng)時(shí)鐘，并使能時(shí)鐘丟失檢測*/
}
void PORT_Init (void)
{
   XBR2    |= 0x44;                    /*使能UART1和交叉開關(guān)，弱上拉*/
   P0MDOUT |= 0x01;                    /*使能TX1推挽輸出*/
   P3MDOUT |= 0x20;                    /*P3.5驅(qū)動(dòng)蜂鳴器*/
   P74OUT  = 0xff;      
}
void UART1_Init (void)
{
   SCON1  = 0x50;                      /*SCON1:模式1, 8-bitUART,使能RX*/
   TMOD   = 0x20;                      /*TMOD: 定時(shí)器1,定時(shí)器2, 8位重載*/  
   //TH1=0xb8;                           /*設(shè)置定時(shí)器1作為波特率的重載值*/
   TH1=-(SYSCLK/BAUDRATE/16);
   TR1    = 1;                         /*開定時(shí)器1*/
   CKCON |= 0x10;                      /*定時(shí)器1用系統(tǒng)時(shí)鐘作為時(shí)基*/
   PCON  |= 0x10;                      /*SMOD1 = 1,波特率加倍*/
   //EIE2  |= 0x40;                    /*使能UART1中斷*/
}
void UART1_ISR (void) interrupt 20 using 3
{
	if((SCON1 & 0x01)==0x01)
	{
		SCON1 &= ~0x01;					/*請接收標(biāo)志位*/
		temp = SBUF1;					/*保存接收數(shù)據(jù)*/
		ReceiveBit=1;					/*置接收位*/
	}
	SCON1 &= ~0x02;						/*清發(fā)送標(biāo)志位*/
}
void LCD_Init(void)
{
	unsigned int x;
	P6 = 0x09;
	for(x=0;x<50000;x++);
   //P7 = 0x30;				/*一行顯示*/
   P7 = 0x38;				/*兩行顯示*/
   P6 = 0x08;
   P6 = 0x09; 
   for(x=0;x<1000;x++);
   P7 = 0x0e;				/*開顯示，開光標(biāo)，字符不閃爍*/
   P6 = 0x08;
   P6 = 0x09;
   for(x=0;x<1000;x++);
   P7= 0x06;				/*I/D=1,AC自動(dòng)增1；S=0,整體顯示不移動(dòng)*/
   P6 = 0x08;
   P6 = 0x09;
   for(x=0;x<5000;x++);
   P7 = 0x01;				/*清除DDRAM,置AC=0*/
   P6 = 0x08;
   P6 = 0x09; 
   for(x=0;x<5000;x++);
}