Linux操作系统下串口编程

时间：2006-06-27 来源：nantianyan

/*----------------------------------------
==========================================
Linux操作系统下串口编程
===========================================
--------------------------------------------*/

#include <stdio.h> /*标准输入输出定义*/
#include <stdlib.h> /*标准函数库定义*/
#include <unistd.h> /*Unix 标准函数定义*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h> /*文件控制定义*/
#include <termios.h> /*PPSIX 终端控制定义*/
#include <errno.h> /*错误号定义*/

#define COM1 1 file://"/dev/ttyS0" file://串口一
#define COM2 2 file://"/dev/ttyS1" file://串口二

#define TURE 0
#define FALSE -1

class Ctermios
{
public:
Ctermios(); file://构造函数
~Ctermios(); file://析构函数
void OpenSerialPort(int); file://打开串口
void CloseSerialPort(); file://关闭串口
void ReadSerialPort(); file://从串口中读取数据
void WriteSerialPort(); file://向串口写入数据
void SetSerialPort();

private:
struct termios opt;
int fd;
char buffR[512];
char buffW[512];
int LenR;
int LenW;

int OpenDev(char *Dev);
void set_speed(int fd,int speed);
int set_Parity(int fd,int databits,int stopbits,int parity);

};
/*--------------------------------------------------
构造函数
---------------------------------------------------*/
Ctermios::Ctermios()
{
struct termios opt;
LenR = 512;
LenW = 512;
}

/*--------------------------------------------------
析构函数
----------------------------------------------------*/
Ctermios::~Ctermios()
{
tcflush(fd,TCIOFLUSH); file://清数据机线并启动序列阜的设定
if(close(fd)==0)
exit(0);
}

/*==================================================================
私有函数初始化串口
===================================================================*/

int Ctermios::OpenDev(char *Dev)
{
int fd = open( Dev, O_RDWR );
file://| O_NOCTTY | O_NDELAY
if (fd == -1)
{
  perror("Can't Open Serial Port"); file://打开串口文件时发生错误
  return -1;
}
else
  return fd; file://返回文件ID
}

/*=========================================================================
设置串口通信速率

fd 类型 int 打开串口的文件句柄
speed 类型 int 串口速度
return void
==========================================================================*/
void Ctermios::set_speed(int fd,int speed)
{
int i;
int status;
int name_arr[]={38400,19200,9600,4800,2400,1200,300, 38400,19200,9600,4800,2400,1200,300 ,};
int speed_arr[]={B38400,B19200,B9600,B4800,B2400,B1200,B300, B38400,B19200,B9600,B4800,B2400,B1200,B300 ,};
struct termios Opt;
tcgetattr(fd,&Opt);
for(i=0;i<sizeof(speed_arr)/sizeof(int);i++)
{
  if (speed==name_arr[i])
  {
   tcflush(fd,TCIOFLUSH);
   cfsetispeed(&Opt,speed_arr[i]);
   cfsetospeed(&Opt,speed_arr[i]);
   status=tcsetattr(fd,TCSANOW,&Opt);
   if (status!=0)
    perror("tcsetattr fd1");
   return;
  }
  tcflush(fd,TCIOFLUSH);
}
}
/*=========================================================================*/

/*==================================================================

私有函数设置校验位

*@brief 设置串口数据位，停止位和效验位
*@param fd 类型 int 打开的串口文件句柄
*@param databits 类型 int 数据位取值为 7 或者8
*@param stopbits 类型 int 停止位取值为 1 或者2
*@param parity 类型 int 效验类型取值为N,E,O,,S
=====================================================================*/
int Ctermios::set_Parity(int fd,int databits,int stopbits,int parity)
{
struct termios options;

if (tcgetattr(fd,&options)!=0)
{
  perror("SetupSerial 1");
  return(FALSE);
}
options.c_cflag&=~CSIZE;

switch(databits)
{
  case 7:
   options.c_cflag|=CS7;
   break;
  case 8:
   options.c_cflag|=CS8;
   break;
  default:
   fprintf(stderr,"Unsuipported data size\n");
   return(FALSE);
}

switch(parity)
{
  case'n':
  case'N':
   options.c_cflag&=~PARENB;
   options.c_iflag&=~INPCK;
   break;
  case'o':
  case'O':
   options.c_cflag|=(PARODD|PARENB);
   options.c_iflag|=INPCK;
   break;
  case'e':
  case'E':
   options.c_cflag|=PARENB;
   options.c_cflag&=~PARODD;
   options.c_iflag|=INPCK;
  break;
  case's':
  case'S':
   options.c_cflag&=~PARENB;
   options.c_cflag&=~CSTOPB;
   break;
  default:
   fprintf(stderr,"Unsupported parity\n");
   return(FALSE);
}

switch(stopbits)
{
  case 1:
   options.c_cflag&=~CSTOPB;
   break;
  case 2:
   options.c_cflag|=CSTOPB;
   break;
  default:
   fprintf(stderr,"Unsupported stop bits\n");
   return(FALSE);
}

if (parity!='n')
  options.c_iflag|=INPCK;

options.c_cc[VTIME]=150;
options.c_cc[VMIN]=0;

tcflush(fd,TCIFLUSH);

if(tcsetattr(fd,TCSANOW,&options)!=0)
{
  perror("SetupSerial 3");
  return(FALSE);
}

return(TURE);
}

/*=========================================================================*/

/*---------------------------------------------------------
公有函数打开串口
-------------------------------------------------------*/
void Ctermios::OpenSerialPort(int com)
{
char *dev ;
switch(com)
{
  case COM1:
  dev = "/dev/ttyS0"; break;
  case COM2:
  dev = "/dev/ttyS1"; break;
  default:
  exit(-1);
}
fd=OpenDev(dev);
set_speed(fd,B9600);

file://@@@@@
if(set_Parity(fd,8,1,'N') == -1)
{
  printf("Set Parity Error\n");
  exit(-1);
}
}

/*---------------------------------------------------------
==========================================================
公有函数设置串口属性
===========================================================
-------------------------------------------------------*/
void Ctermios::SetSerialPort()
{
int sp;
printf("please input baute rate\n");
printf("default rate please input 9600");
scanf("%d",&sp);
set_speed(fd,sp);
int dt,st;
printf("please input databits stopbits \n");
printf("default rate please input 8 1 ");
scanf("%d %d",&dt,&st);
if(set_Parity(fd,dt,st,'N')==FALSE)
{
printf("Set Parity Error\n");
exit(0);
}
}

/*---------------------------------------------------------
==========================================================
公有函数读取串口信息
===========================================================
-------------------------------------------------------*/
void Ctermios::ReadSerialPort()
{
int nread;
while(nread!=0)
{
  while((nread=read(fd,buffR,511)>0))
  {
   printf("\nLen %d\n",nread);
   buffR[nread+1]='\0';
   printf("\n%s",buffR);
  }
  if (nread==-1)
  {
   printf("read error!\n");
   exit(-1);
  }
}
}

/*---------------------------------------------------------
==========================================================
公有函数发送串口信息
===========================================================
-------------------------------------------------------*/
void Ctermios::WriteSerialPort()
{
int nwrite;
char bb;
int i;
while(nwrite!=-1)
{
  for(i=0;i<512;i++)
  {
   bb=getchar();
   buffW[i]=bb;
  }
  nwrite=write(fd,buffW,512);
}
}

/*---------------------------------------------------------
==========================================================
公有函数关闭串口
===========================================================
-------------------------------------------------------*/

void Ctermios::CloseSerialPort()
{
close(fd);
}