linux+串口通讯源码.txt

ARM2410的串口驱动。苏东海村vsdhvoisdv

主要函数

int openport(char *Dev) //打开串口 

int setport(int fd, int baud,int databits,int stopbits,int parity)//设置串口，波特率，数据位，停止位，校验 


int readport(int fd,char *buf,int len,int maxwaittime)//读数据，参数为串口，BUF，长度，超时时间 


int writeport(int fd,char *buf,int len)  //发送数据 



void clearport(int fd)      //如果出现数据与规约不符合，可以调用这个函数来刷新串口读写数据  

  



#include   <stdio.h>   
#include   <string.h>   
#include   <unistd.h>   
#include   <fcntl.h>   
#include   <errno.h>   
#include   <termios.h>   
#include   <sys/time.h> 
int openport(char *Dev)   
 {
 int fd = open( Dev, O_RDWR|O_NOCTTY|O_NDELAY ); 
 if (-1 == fd) 
 {    
  perror("Can''t Open Serial Port");
  return -1;  
 } 
 else 
  return fd;  

 }   
    
int setport(int fd, int baud,int databits,int stopbits,int parity)
{
 int baudrate;
 struct   termios   newtio;   
 switch(baud)
 {
 case 300:
  baudrate=B300;
  break;
 case 600:
  baudrate=B600;
  break;
 case 1200:
  baudrate=B1200;
  break;
 case 2400:
  baudrate=B2400;
  break;
 case 4800:
  baudrate=B4800;
  break;
 case 9600:
  baudrate=B9600;
  break;
 case 19200:
  baudrate=B19200;
  break;
 case 38400:
  baudrate=B38400;
  break;
 default :
  baudrate=B9600;  
  break;
 }
 tcgetattr(fd,&newtio);     
 bzero(&newtio,sizeof(newtio));    
   //setting   c_cflag 
 newtio.c_cflag   &=~CSIZE;     
 switch (databits) /*设置数据位数*/
 {   
 case 7:  
  newtio.c_cflag |= CS7; //7位数据位
  break;
 case 8:     
  newtio.c_cflag |= CS8; //8位数据位
  break;   
 default:    
  newtio.c_cflag |= CS8;
  break;    
 }
 switch (parity) //设置校验
 {   
 case 'n':
 case 'N':    
  newtio.c_cflag &= ~PARENB;   /* Clear parity enable */
  newtio.c_iflag &= ~INPCK;     /* Enable parity checking */ 
  break;  
 case 'o':   
 case 'O':     
  newtio.c_cflag |= (PARODD | PARENB); /* 设置为奇效验*/  
  newtio.c_iflag |= INPCK;             /* Disnable parity checking */ 防采集 
  break;  
 case 'e':  
 case 'E':   
  newtio.c_cflag |= PARENB;     /* Enable parity */    
  newtio.c_cflag &= ~PARODD;   /* 转换为偶效验*/     
  newtio.c_iflag |= INPCK;       /* Disnable parity checking */
  break;
 case 'S': 
 case 's':  /*as no parity*/   
     newtio.c_cflag &= ~PARENB;
  newtio.c_cflag &= ~CSTOPB;break;  
 default:   
  newtio.c_cflag &= ~PARENB;   /* Clear parity enable */
  newtio.c_iflag &= ~INPCK;     /* Enable parity checking */ 
  break;   
 } 
 switch (stopbits)//设置停止位
 {   
 case 1:    
  newtio.c_cflag &= ~CSTOPB;  //1
  break;  



 case 2:    
  newtio.c_cflag |= CSTOPB;  //2
    break;
 default:  
  newtio.c_cflag &= ~CSTOPB;  
  break;  
 } 
 newtio.c_cc[VTIME] = 0;    
 newtio.c_cc[VMIN] = 0; 
 newtio.c_cflag   |=   (CLOCAL|CREAD);
 newtio.c_oflag|=OPOST; 
 newtio.c_iflag   &=~(IXON|IXOFF|IXANY);                     
    cfsetispeed(&newtio,baudrate);   
    cfsetospeed(&newtio,baudrate);   
    tcflush(fd,   TCIFLUSH); 
 if (tcsetattr(fd,TCSANOW,&newtio) != 0)   
 { 
  perror("SetupSerial 3");  
  return -1;  
 }  
 return 0;
} 不能采集本站 
int readport(int fd,char *buf,int len,int maxwaittime)//读数据，参数为串口，BUF，长度，超时时间
{
 int no=0;int rc;int rcnum=len;
 struct timeval tv;
 fd_set readfd;
 tv.tv_sec=maxwaittime/1000;    //SECOND
 tv.tv_usec=maxwaittime%1000*1000;  //USECOND
 FD_ZERO(&readfd);
 FD_SET(fd,&readfd);
 rc=select(fd+1,&readfd,NULL,NULL,&tv);
 if(rc>0)
 {
  while(len)
  {
   rc=read(fd,&buf[no],1);
   if(rc>0)
    no=no+1;
   len=len-1;   
  }
  if(no!=rcnum)
   return -1;      //如果收到的长度与期望长度不一样，返回-1
  return rcnum;      //收到长度与期望长度一样，返回长度
 }
 else
 {
  return -1;
 }
 return -1;
}
int writeport(int fd,char *buf,int len)  //发送数据  
{
 write(fd,buf,len);
}
void clearport(int fd)      //如果出现数据与规约不符合，可以调用这个函数来刷新串口读写数据
{
 tcflush(fd,TCIOFLUSH);
}
main()   
{   
 int   fd,rc,i,ret;   
 unsigned char rbuf[256]; 
 unsigned char wbuf[256]="";
 for(i=0;i<256;i++)
  wbuf[i]=i;
 char *dev ="/dev/ttyS0";    //串口号 /dev/ttyS0  对应于串口1
    fd  =  openport(dev);     //打开串口
 if(fd>0)
 {
  ret=setport(fd,4800,8,1,'o');  //设置串口，波特率，数据位，停止位，校验
  if(ret<0)
  {
   printf("Can't Set Serial Port!\n");
   exit(0);
  }
 }
 else
 {
  printf("Can't Open Serial Port!\n");
  exit(0); 


 }
 while(1){  
  rc=readport(fd,rbuf,5,500);   //读取5个字节，超时时间为500毫秒
  if(rc>0)
  {
   writeport(fd,wbuf,rc);
   printf("recv:%d\n",rc);
   for(i=0;i<rc;i++)
   printf("%02x ",rbuf[i]);
   printf("\n");
  }
  else
   printf("recv none\n");  
 }   
 close(fd);   
}