/*
	main.c
	串行口通信方式3例程
*/


#include <reg51.h>


//參數(shù)配置
#define MCLK		11059200L	//定義CPU主頻(Hz)
#define BAUD_RATE	9600L		//設(shè)置波特率


//定義發(fā)送輔助標(biāo)志
static volatile bit _TI_;


//定義接收緩沖區(qū)
#define SIZE	40
unsigned char UartBuf[SIZE];


//定義接收緩沖區(qū)下標(biāo)變量
unsigned char BufP1;
unsigned char BufP2;


/*
函數(shù)：UartInit()
功能：串行口初始化
*/
void UartInit()
{
	unsigned char i;
	EA = 0;
	BufP1 = 0;
	BufP2 = 0;
	for ( i=0; i<SIZE; i++ )
	{
		UartBuf[i] = 0x00;
	}
	TR1 = 0;
	RXD = 1;
	TXD = 1;
	_TI_ = 1;
	SCON = 0xD0;	//串口方式3（9位Uart），允許接收
	PCON |= 0x80;	//波特率加倍
	TMOD &= 0x0F;
	TMOD |= 0x20;
	TH1 = 256 - ( MCLK / 12 ) / ( 16 * BAUD_RATE );
	TL1 = TH1;		//設(shè)置波特率
	TR1 = 1;
	ES = 1;			//允許串行口中斷
	EA = 1;			//允許中斷
}


/*
函數(shù)：UartINTSVC
功能：串行口中斷服務(wù)程序
*/
void UartINTSVC() interrupt 4
{
	char c;
	if ( RI )	//接收中斷
	{
		c = SBUF;
		RI = 0;
		ACC = c;
		F0 = P;
		if ( F0 == RB8 )
		{
			UartBuf[BufP1++] = c;
			if ( BufP1 >= SIZE )
			{
				BufP1 = 0;
			}
		}
	}
	if ( TI )	//發(fā)送中斷
	{
		TI = 0;
		_TI_ = 1;
	}
}


/*
函數(shù)：UartSendChar()
功能：通過(guò)串行口發(fā)送單個(gè)字節(jié)
參數(shù)：
	c：被發(fā)送的字節(jié)數(shù)據(jù)，取值0x00～0xFF
*/
void UartSendChar(char c)
{
	while ( !_TI_ );
	_TI_ = 0;
	ACC = c;
	TB8 = P;
	SBUF = c;
}


void main()
{
	UartInit();
	for (;;)
	{
		if ( BufP2 != BufP1 )
		{
			UartSendChar(UartBuf[BufP2++]);
			if ( BufP2 >= SIZE )
			{
				BufP2 = 0;
			}
		}
	}
}