a linux serial port test program.htm

来自「linux串口编程的一些文档以及一些示例」· HTM 代码 · 共 530 行 · 第 1/2 页

      newkey.c_cc[VTIME]=0;
      tcflush(tty, TCIFLUSH);
      tcsetattr(tty,TCSANOW,&newkey);

      switch (Baud_Rate)
      {
         case 38400:
         default:
            BAUD = B38400;
            break;
         case 19200:
            BAUD  = B19200;
            break;
         case 9600:
            BAUD  = B9600;
            break;
         case 4800:
            BAUD  = B4800;
            break;
         case 2400:
            BAUD  = B2400;
            break;
         case 1800:
            BAUD  = B1800;
            break;
         case 1200:
            BAUD  = B1200;
            break;
         case 600:
            BAUD  = B600;
            break;
         case 300:
            BAUD  = B300;
            break;
         case 200:
            BAUD  = B200;
            break;
         case 150:
            BAUD  = B150;
            break;
         case 134:
            BAUD  = B134;
            break;
         case 110:
            BAUD  = B110;
            break;
         case 75:
            BAUD  = B75;
            break;
         case 50:
            BAUD  = B50;
            break;
      }  //end of switch baud_rate
      switch (Data_Bits)
      {
         case 8:
         default:
            DATABITS = CS8;
            break;
         case 7:
            DATABITS = CS7;
            break;
         case 6:
            DATABITS = CS6;
            break;
         case 5:
            DATABITS = CS5;
            break;
      }  //end of switch data_bits
      switch (Stop_Bits)
      {
         case 1:
         default:
            STOPBITS = 0;
            break;
         case 2:
            STOPBITS = CSTOPB;
            break;
      }  //end of switch stop bits
      switch (Parity)
      {
         case 0:
         default:                       //none
            PARITYON = 0;
            PARITY = 0;
            break;
         case 1:                        //odd
            PARITYON = PARENB;
            PARITY = PARODD;
            break;
         case 2:                        //even
            PARITYON = PARENB;
            PARITY = 0;
            break;
      }  //end of switch parity
       
      //open the device(com port) to be non-blocking (read will return immediately)
      fd = open(devicename, O_RDWR | O_NOCTTY | O_NONBLOCK);
      if (fd < 0)
      {
         perror(devicename);
         exit(-1);
      }

      //install the serial handler before making the device asynchronous
      saio.sa_handler = signal_handler_IO;
      sigemptyset(&saio.sa_mask);   //saio.sa_mask = 0;
      saio.sa_flags = 0;
      saio.sa_restorer = NULL;
      sigaction(SIGIO,&saio,NULL);

      // allow the process to receive SIGIO
      fcntl(fd, F_SETOWN, getpid());
      // Make the file descriptor asynchronous (the manual page says only
      // O_APPEND and O_NONBLOCK, will work with F_SETFL...)
      fcntl(fd, F_SETFL, FASYNC);

      tcgetattr(fd,&oldtio); // save current port settings 
      // set new port settings for canonical input processing 
      newtio.c_cflag = BAUD | CRTSCTS | DATABITS | STOPBITS | PARITYON | PARITY | CLOCAL | CREAD;
      newtio.c_iflag = IGNPAR;
      newtio.c_oflag = 0;
      newtio.c_lflag = 0;       //ICANON;
      newtio.c_cc[VMIN]=1;
      newtio.c_cc[VTIME]=0;
      tcflush(fd, TCIFLUSH);
      tcsetattr(fd,TCSANOW,&newtio);

      // loop while waiting for input. normally we would do something useful here
      while (STOP==FALSE)
      {
         status = fread(&Key,1,1,input);
         if (status==1)  //if a key was hit
         {
            switch (Key)
            { /* branch to appropiate key handler */
               case 0x1b: /* Esc */
                  STOP=TRUE;
                  break;
               default:
                  fputc((int) Key,output);
//                  sprintf(message,"%x ",Key);  //debug
//                  fputs(message,output);
                  write(fd,&Key,1);          //write 1 byte to the port
                  break;
            }  //end of switch key
         }  //end if a key was hit
         // after receiving SIGIO, wait_flag = FALSE, input is available and can be read
         if (wait_flag==FALSE)  //if input is available
         {
            res = read(fd,buf,255);
            if (resɬ)
            {
               for (i=0; i<res; i++)  //for all chars in string
               {
                  In1 = buf[i];
                  switch (Format)
                  {
                     case 1:         //hex
                        sprintf(message,"%x ",In1);
                        fputs(message,output);
                        break;
                     case 2:         //decimal
                        sprintf(message,"%d ",In1);
                        fputs(message,output);
                        break;
                     case 3:         //hex and asc
                        if ((In1ថ) || (In1))
                        {
                           sprintf(message,"%x",In1);
                           fputs(message,output);
                        }
                        else fputc ((int) In1, output);
                        break;
                     case 4:         //decimal and asc
                     default:
                        if ((In1ថ) || (In1))
                        {
                           sprintf(message,"%d",In1);
                           fputs(message,output);
                        }
                        else fputc ((int) In1, output);
                        break;
                     case 5:         //asc
                        fputc ((int) In1, output);
                        break;
                  }  //end of switch format
               }  //end of for all chars in string
            }  //end if resɘ
//            buf[res]=0;
//            printf(":%s:%d\n", buf, res);
//            if (res==1) STOP=TRUE; /* stop loop if only a CR was input */
            wait_flag = TRUE;      /* wait for new input */
         }  //end if wait flag == FALSE

      }  //while stop==FALSE
      // restore old port settings
      tcsetattr(fd,TCSANOW,&oldtio);
      tcsetattr(tty,TCSANOW,&oldkey);
      close(tty);
      close(fd);        //close the com port
   }  //end if command line entrys were correct
   else  //give instructions on how to use the command line
   {
      fputs(instr,output);
      fputs(instr1,output);
      fputs(instr2,output);
      fputs(instr3,output);
      fputs(instr4,output);
      fputs(instr5,output);
      fputs(instr6,output);
      fputs(instr7,output);
   }
   fclose(input);
   fclose(output);
}  //end of main

/***************************************************************************
* signal handler. sets wait_flag to FALSE, to indicate above loop that     *
* characters have been received.                                           *
***************************************************************************/

void signal_handler_IO (int status)
{
//    printf("received SIGIO signal.\n");
   wait_flag = FALSE;
}
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                  <H3>An example invocation of this program</H3>
                  <P>This program will allow a user to communicate from one 
                  computer to another using two serial lines. It is intended 
                  only as a test for the serial connection allowing any possible 
                  serial setting. This program is named com when compiled. To 
                  use it, the following is an example command line: </P>
                  <P class=indent>com /dev/ttyS0 38400 8 1 0 4 </P>
                  <P>This line works for com1 at 38400 baud, 8 data bits. I make 
                  it a file, call it "fcom1" and put it in my system path and 
                  invoke it as a script program. </P><!--Begin TechTutorials.info Banner code -->
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                  href="http://www.comptechdoc.org/os/linux/programming/c/linux_pgc.html" 
                  target=_top>Linux C Programmer's Guide Contents 
                Page</A></DIV></TD></TR></TBODY></TABLE></TR></TBODY></TABLE></TR></TBODY></TABLE></BODY></HTML>