serial_comm_3.c

单片机像计算机发送、接收数据、串口中断、蓝牙通讯

/**********************************************
*   File: Serial_Comm_3.C
*   Description: Serial Communication Example 3 Echo
*   Created Date:  2007-10-01
*   Last Modified: 2007-10-01
*   Author: Jeffrey - [e-mail]
*   Notes: None
**********************************************/
#include "Atmel/AT89X51.h"

#define BUFFER_LENGTH 50
unsigned char _Buffer[50];
unsigned char pWrite = 0;
unsigned char pRead = 0;
unsigned char UpdateFlag = 0;
unsigned char OverflowFlag = 0;
unsigned char LoopFlag = 0;
void RS232_SendData(unsigned char Sdata);
unsigned char ReadBuffer();

/**********************************************
*   Function: delay(unsigned int t)
*   Input Variables: t
*   Return Variables: None
*   Usage: Common Delay Routine, t as the delay time ticks
**********************************************/
void delay(unsigned int t)
{
		for(;t>0;t--);		// 延时循环
}

/**********************************************
*   Function: RS232_Init(void)
*   Input Variables: none
*   Return Variables: None
*   Usage: Init UART
**********************************************/
void RS232_Init()
{
	SCON = 	0x50;		// UART工作于模式1， REN=1 
	TMOD = 	0x20 ;		// Timer1 工业于模式2
	PCON |= 0x80;		// SMOD1 = 1 
	TH1	= 0xF3;			// 波特率9600 Bds at 24MHz 
	TL1	= 0xF3;			// 波特率9600 Bds at 24MHz 
	ES 	= 1; 			// 串口中断使能	
	TR1 = 1; 			// 启动Timer1 
}

/**********************************************
*   Function: main()
*   Input Variables: None
*   Return Variables: None
*   Usage: Program Entry
*********************************************/
void main()
{
		unsigned char RevData;						// 接收数据
		unsigned char LED;						    // LED跑马灯状态
		RS232_Init();								// 初始化UART
		EA = 1;										// 全局中断使能
		while(1)
		{
				//********************主程序部分*********************//
				if(UpdateFlag)
				{
					RevData = ReadBuffer();				// 读取数据
					LED = ~RevData;						// 设置LED灯状态
					P0 = LED;							// 点亮相应LED
					RS232_SendData(RevData);            // 发送数据
				}
				//********************主程序部分*********************//
		}
}

/**********************************************
*   Function: ReadBuffera(void)
*   Input Variables: void
*   Return Variables: unsigned char
*   Usage: read a char from the Buffer
*********************************************/
unsigned char ReadBuffer()
{
		unsigned char Buffer_value;			// Buffer 值
		Buffer_value = _Buffer[pRead];	    // 从缓存区读数
		pRead++;							// 指针向前移动
		if(pRead == BUFFER_LENGTH)		    // 如果到缓存末尾
		{
  	 		pRead = 0;						// 循环指针
  	 		LoopFlag = 0;					// 清除LoopFlag
		}	
  	
		if((pRead == pWrite) && (!LoopFlag)) // 如果数据读取完毕
		{ 
			UpdateFlag = 0;                  // 清除更新标志                 
		}
		
		if(OverflowFlag) 					 // 如果数据缓存溢出
		{
			OverflowFlag = 0;				 // 清除数据溢出标志 
		}
		return Buffer_value;				 // 返回读取值
}

/**********************************************
*   Function: RS232_SendData(unsigned char Sdata)
*   Input Variables: unsigned char Sdata
*   Return Variables: none
*   Usage: Send a Char to UART
*********************************************/
void RS232_SendData(unsigned char Sdata)
{
	while(TI==0);		// 等待发送完毕
	SBUF = Sdata;		// 发送数据
}

/**********************************************
*   Function: serial_IT
*   Input Variables: void
*   Return Variables: void
*   Usage: UART Interrupt Service Routine
*********************************************/
void serial_IT(void) interrupt SIO_VECTOR 
{
	EA = 0;						 // 关中断
	if (RI == 1) 
	{						 	 // 接收中断
		RI = 0; 			 	 // 清除中断标志 
		_Buffer[pWrite] = SBUF;	 // 将数据写入缓存区
		UpdateFlag = 1;			 // 置高数据更新标志
		pWrite++;
		if(pWrite == BUFFER_LENGTH)
		{
	  	 	pWrite = 0;			 // 循环缓存区
	  	 	LoopFlag = 1;		 // 置高Loop标志
		}
		if((pWrite >= pRead) && (LoopFlag == 1))
		{
			OverflowFlag = 1;    // 数据溢出标志置高
		}
	}
	else
	{
		TI = 0;				// 清除发送中断标志
	}
	EA = 1;	 				// 开中断，准备下次接收		
}