51单片机串口接收和发送数据

第一种方法：在中断中处理

typedef unsigned char         UINT8;
volatile  UINT8 u8Uart_Data;
void InitialUART0_Timer1()
{

    SCON = 0x50;        //2015-05-04
    TMOD = 0x20;

    TH1 = 0XFD;                              // 9600BPS     2015-05-04     wangrong
    TL1 = 0XFD;
    TR1 = 1;                               // start timer0
    ES = 1;                             // Enable serial interrupt
    EA = 1;                             // Enable global interrupt
}

//-----------------------------------------------------------------------------------------------------------
void main (void)
{

    //--------------------------------------------------------------------------------
    InitialUART0_Timer1();                   // 9600 Baud Rate @ 11.0592MHz

    while(1)
    {
         //    Receive_Data_From_PC();
        //Send_Data_To_PC(Receive_Data_From_PC());
        while(recv_data)
        {
            recv_data = 0;
            TI = 0;
            SBUF = u8Uart_Data;
        }

    }
}
//-----------------------------------------------------------------------------------------------------------
void UART_ISR(void) interrupt 4
{
    if (RI)
    {                                   // If reception occur
        RI = 0;                         // Clear reception flag for next reception
        u8Uart_Data = 0;
        u8Uart_Data = SBUF;             // Read receive data
        recv_data = 1;
        //SBUF = u8Uart_Data;           // Send back same data on UART
       }
    if (TI)                                // If emission occur
    {                                   // Clear emission flag for next emission
        TI = 0;
    }
}
//-----------------------------------------------------------------------------------------------------------

第二种方法：不在中断中处理

//-----------------------------------------------------------------------------------------------------------
// Use timer1 as baud rate generator
void InitialUART0_Timer1()
{

    SCON = 0x50;        //2015-05-04
    TMOD = 0x20;

#if 0

#ifdef FOSC_110592
    TH1 = 256 - (28800/u32Baudrate); /* 11.059M/384=28800 */
#endif
#ifdef FOSC_184320
    TH1 = 256 - (48000/u32Baudrate); /* 18.4320M/384=48000 */
#endif
#ifdef FOSC_221184
     TH1 = 256 - (57600/u32Baudrate); /* 22.1184M/384=57600 */
#endif
#ifdef FOSC_331776
     TH1 = 256 - (86400/u32Baudrate); /* 33.1776M/384=86400 */
#endif
#ifdef FOSC_368640
     TH1 = 256 - (96000/u32Baudrate); /* 36.8640M/384=96000 */
#endif

#endif /*    #if 0    */

    TH1 = 0XFD;                              // 9600BPS     2015-05-04     wangrong
    TL1 = 0XFD;
    TR1 = 1;                               // start timer0
    ES = 1;                             // Enable serial interrupt
    EA = 1;                             // Enable global interrupt
}
//-----------------------------------------------------------------------------------------------------------
UINT8 Receive_Data_From_PC(void)
{
    UINT8 c;

    while (!RI);
    c = SBUF;
    RI = 0;
    return (c);
}
//-----------------------------------------------------------------------------------------------------------
void Send_Data_To_PC (UINT8 c)
{
    while (!TI);
    TI = 0;
    SBUF = c;
}
//-----------------------------------------------------------------------------------------------------------

//-----------------------------------------------------------------------------------------------------------
void main (void)
{

    //--------------------------------------------------------------------------------

    InitialUART0_Timer1();                   // 9600 Baud Rate @ 11.0592MHz

    //---------------------------------------------------------------------------------

    while(1)
    {

         Receive_Data_From_PC();
        Send_Data_To_PC(Receive_Data_From_PC());
    }
}