rs485txd.c

基于51单片机

/***********************************************
                 主机
**********************************************/
#include<reg52.h>
#define uchar unsigned char

sbit led = P1^0;
sbit EN = P1^1;
uchar code uart_table[]={0x04,0x00,0x11,0x22,0x33
};                          //第一个数是发射字节长度
void delay(uchar x)
{
	while(x--);
}

void main (void) 
{
    uchar i;
    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 */
    IE =0x90;
    TR1 = 1;                     /* Timer 1 run */
    EN = 1;                        /* RS-485 enable,'0'--RX enable; '1'--TX disable */
                              
   while(1)                     
   {          for(i=0;i<5;i++)     //sent bytes         
           {                                    
              SBUF=uart_table[i];                                     
              while(TI==0);                                               
              TI=0;
            }
             led = 0;          //发送完点亮灯 
}
}