1.先从wiringpi库复制一个串口代码

2.查看串口类型

3.将代码修改成ttyS5

4.改完代码后打开串口助手然后编译

 代码示例：

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <pthread.h>
#include <wiringPi.h>
#include <wiringSerial.h>
#include <stdlib.h>
#include <unistd.h>
int fd;

void* Sendhandler()
{
        char *sendbuf;
        sendbuf = (char *)malloc(32*sizeof(32));

        while(1){
                memset(sendbuf,'\0',32);
                scanf("%s",sendbuf);
                while(*sendbuf){
                        serialPutchar(fd,*sendbuf++);
                }
        }
}

void* Revhandler()
{
        while(1){
                while(serialDataAvail(fd))
                {
                        printf("%c",serialGetchar(fd));
                        fflush(stdout);
                }
        }
}

int main ()
{
  int count ;
  unsigned int nextTime ;

  pthread_t idSend;
  pthread_t idRev;

  if ((fd = serialOpen ("/dev/ttyS5", 115200)) < 0)
  {
    fprintf (stderr, "Unable to open serial device: %s\n", strerror (errno)) ;
    return 1 ;
  }

  pthread_create(&idSend,NULL,Sendhandler,NULL);
  pthread_create(&idRev,NULL,Revhandler,NULL);

  if (wiringPiSetup () == -1)
  {
    fprintf (stdout, "Unable to start wiringPi: %s\n", strerror (errno)) ;
    return 1 ;
  }

  while(1){
          sleep(10);
  }

  printf ("\n") ;
  return 0 ;
}