uart_t2.c

NPI单片机C语言编写的EEPROM读写程序,单片机为AT89C51ED2.

/**
 * @file $RCSfile: uart_t2.c,v $
 *
 * Copyright (c) 2004 Atmel.
 *
 * Please read file license.txt for copyright notice.
 *
 * @brief This file is an example to use uart with timer2.
 * 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 2 in baud rate generator mode.
 * FUNCTION_INPUTS: void
 * FUNCTION_OUTPUTS: void
 */
void main (void) 
{
	SCON = 0x50;					  /* uart in mode 1 (8 bit), REN=1 */
   T2CON &= 0xF0;               /* EXEN2=0; TR2=0; C/T2#=0; CP/RL2#=0; */
   T2CON |= 0x30;               /* RCLK = 1; TCLK=1; */
   TH2=0xFF;                    /* init value */
   TL2=0xFD;                    /* init value */
   RCAP2H=0xFF;                 /* reload value, 115200 Bds at 11.059MHz */
   RCAP2L=0xFD;                 /* reload value, 115200 Bds at 11.059MHz */
	ES = 1; 						     /* Enable serial interrupt */
	EA = 1;						     /* Enable global interrupt */
   TR2 = 1;                     /* Timer 2 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*/		
}