[QLdsPIC3]串口通信[dsPIC33FJ128GP708+C30]

#include <p33Fxxxx.h>

_FOSCSEL(FNOSC_PRIPLL);   // Primary (XT, HS, EC) Oscillator with PLL

_FOSC(FCKSM_CSDCMD & OSCIOFNC_OFF  & POSCMD_HS);  
        // Clock Switching and Fail Safe Clock Monitor is disabled
        // OSC2 Pin Function: OSC2 is Clock Output
        // Primary Oscillator Mode: EC, External
        
_FWDT(FWDTEN_OFF);              // Watchdog Timer Enabled/disabled by user software
        // (LPRC can be disabled by clearing SWDTEN bit in RCON register

void ini232(void);                
void __attribute__((__interrupt__)) _U2RXInterrupt(void); /*Declare 232 interrupt ISRs*/

unsigned char rxdata1;            //定义接收数据缓存变量

//******************主函数*************************
int main (void)
{ 
unsigned char i;
ini232();                         //调用RS232口初始化函数
for(i=100;i>0;i--);               //延长时间以保证可靠初始化    
while(1);              
}

//*************RS232初始化函数**********************
void ini232(void)
{

// Fin=10M
// Fosc= Fin*M/(N1*N2), Fcy=Fosc/2
// Fosc= 10*24/(2*2)=60
// Fcy, Instruction Clock = Fosc/2 = 30MHz

 PLLFBD=22;     // M=24
 CLKDIVbits.PLLPOST=0;  // N1=2
 CLKDIVbits.PLLPRE=0;  // N2=2
 
// Disable Watch Dog Timer
    RCONbits.SWDTEN=0;

// Wait for PLL to lock
 while(OSCCONbits.LOCK!=1) {};

  TRISDbits.TRISD2 =0;

  TRISFbits.TRISF2 =1;            //RC脚输入  
  TRISFbits.TRISF3 =1;            //TX脚输出
//  IPC6bits.U2RXIP=7;              //中断优先级别
  IEC0bits.U1TXIE=0;              //禁止发送中断
  IEC0bits.U1RXIE=1;              //使能接收中断
  U1BRG =110;  //27;              //波特率设置为19200
  U1MODE =0x8800;                 //使能UART功能
  U1STA=0X0000;    
  U1STAbits.UTXEN =1;             //允许发送    
}

//************接收中断函数**************************
void __attribute__((__interrupt__)) _U1RXInterrupt(void)
{
IFS0bits.U1RXIF = 0;              //清除中断标志位
while(U1STAbits.URXDA)            //读取接收到的所有数据
 {
    rxdata1=U1RXREG;              //缓存接收的数据
    if(rxdata1==0x55) PORTDbits.RD2 =1;
    U1TXREG=rxdata1& 0xFF;              //把接收到的数据发送回去
//     U2TXREG=0x55;
    while(U1STAbits.TRMT==0);     //等待发送完毕
 }  
}