uart_t1.c

Atmel Uart C51程序（timer1方式）

/**
 * @file $RCSfile: uart_t1.c,v $
 *
 * Copyright (c) 2004 Atmel.
 *
 * Please read file license.txt for copyright notice.
 *
 * @brief This file is an example to use uart with timer1.
 * UART will echo a received data.
 *
 * This file can be parsed by Doxygen for automatic documentation
 * generation.
 * Put here the functional description of this file within the software
 * architecture of your program.
 *
 * @version $Revision: 1.0 $ $Name:  $
 */

/* @section  I N C L U D E S */
#include "reg_c51.h"

char uart_data;

/**
 * FUNCTION_PURPOSE: This file set up uart in mode 1 (8 bits uart) with
 * timer 1 in mode 2 (8 bits auto reload timer).
 * FUNCTION_INPUTS: void
 * FUNCTION_OUTPUTS: void
 */
void main (void) 
{
	SCON = 0x50;					  /* uart in mode 1 (8 bit), REN=1 */
	TMOD = TMOD | 0x20 ;         /* Timer 1 in mode 2 */
	TH1  = 0xFD;                 /* 9600 Bds at 11.059MHz */
	TL1  = 0xFD; 				  	  /* 9600 Bds at 11.059MHz */
	ES = 1; 						     /* Enable serial interrupt	*/
	EA = 1;						     /* Enable global interrupt */
	TR1 = 1; 						  /* Timer 1 run */

   while(1);                    /* endless */
}		

/**
 * FUNCTION_PURPOSE: serial interrupt, echo received data.
 * FUNCTION_INPUTS: P3.0(RXD) serial input
 * FUNCTION_OUTPUTS: P3.1(TXD) serial output
 */
void serial_IT(void) interrupt 4 
{

	if (RI == 1) 
	{				                 /* if reception occur */
	  RI = 0; 			           /* clear reception flag for next reception */
	  uart_data = SBUF;          /* Read receive data */
	  SBUF = uart_data; 	        /* Send back same data on uart*/
	}
	else TI = 0;        /* if emission occur */
	  		              /* clear emission flag for next emission*/		
}