使用C＃和C语言进行USB到串行（往返）通信

Question

This is the 1st time am posting my query. I am in need of help. Any help is appreciated.

As i agree that i have given my prob as long story. But am sorry i am not getting how to make it short and my intention is give complete information regarding my prob.

Problem : I have to communicate between two laptops using USB-to-Serial adapter on windows platform. I have written 2 programs one for sending and another for receiving. Programs were written in both C and C# programming languages.

Using C language : I am able to successfully communicate using C-Programs mentioned below. But the problem is speed. It takes around 1 hour(60min) for just to pass 150MB. Anyone plz help me in improving the performance of this programs or you may suggest me other approaches which is robust and give high performance. I also mention some comments along with programs for self understanding.

Sender File on laptop with serial port :

#include <stdio.h>
#include <bios.h>
#include <conio.h>
#define COM1       0
#define DATA_READY 0x100
#define TRUE       1
#define FALSE      0
#define SETTINGS ( 0xE0 | 0x03 | 0x00 | 0x00)

int main(void)
{
   int in, out, status, DONE = FALSE,i=0;
   char c;
   FILE *fp,*fp1;
   unsigned long count = 0,shiftcount = 0;

   clrscr();

   fp = fopen("C:/TC/pic.jpg","rb"); //opened for reading actual content
   fp1 = fopen("C:/TC/pic.jpg","rb"); //opened for reading the size of file

   fseek(fp1,0L,2);
   count = ftell(fp1) + 1; // file size

   bioscom(0, SETTINGS, COM1); // initializing the port

   printf("No. of Characters = %lu\n",count);

// since bioscom function can send or receive only 8bits at a time, am sending file size in
    4 rounds so that we can send at max of 4GB file.

   bioscom(1,count,COM1); // sneding 1st lower 8bits 

   bioscom(1,count>>8,COM1); // sending 2nd set of lower 8bits

   bioscom(1,count>>16,COM1); // sending 3rd set of lower 8bits

   bioscom(1,count>>24,COM1); // sending upper 8 bits

   cprintf("... BIOSCOM [ESC] to exit ...\n");
   while (!DONE)
   {
      status = bioscom(3, 0, COM1);// get the status of port
      //printf("%d",status);
      if (status & DATA_READY) //checks if data is ready
      {
        out = bioscom(2, 0, COM1); // receives the ack
        if(!feof(fp))
        {
            c = fgetc(fp); //read character by character from file
            bioscom(1,c,COM1);//send character to receiver
            putch(c);//display
        }
     }

//to interrupt
     if (kbhit())
     {
        if ((in = getch()) == '\x1B')
           DONE = TRUE;
     }
   }
   fclose(fp);
   return 0;
}

Receiving file on laptop with USB port :

#include <stdio.h>
#include <bios.h>
#include <conio.h>

#define COM4       3
#define DATA_READY 0x100
#define TRUE       1
#define FALSE      0

#define SETTINGS ( 0xE0 | 0x03 | 0x00 | 0x00)

int main(void)
{
   int in, out, status;
   char c;
   FILE *fp;
   unsigned long shiftcount1=0,shiftcount2=0,shiftcount3=0,shiftcount4=0;
   unsigned long count = 0, DONE = 1;

   clrscr();

   fp = fopen("C:/TC/pic1.jpg","wb");// file opened for writing

   bioscom(0, SETTINGS, COM4);//initialize tyhe port
   cprintf("... BIOSCOM [ESC] to exit ...\n");
//receives all the 32 bits of file size sent from sender
   shiftcount1 = bioscom(2,0,COM4);
   shiftcount2 = bioscom(2,0,COM4);
   shiftcount3 = bioscom(2,0,COM4);
   shiftcount4 = bioscom(2,0,COM4);

//send an ack
   bioscom(1,'x',COM4);

   count = shiftcount1 | (shiftcount2<<8) | (shiftcount3<<16) | (shiftcount4<<24);

   printf("shift4 = %lu\tshift3 = %lu\tshift2 = %lu\tshift1 = %lu\n",shiftcount4,shiftcount3,shiftcount2,shiftcount1);
   printf("File Size = %lu\n",count);

//loop till the size of the file
   while (DONE < count)
   {
      status = bioscom(3, 0, COM4);// check the status
     // printf("%d",status);
      if (status & DATA_READY)//check for data ready at the port
      {
        out = bioscom(2, 0, COM4);//receive the data
        DONE++;
        fputc(out,fp);
        putch(out);
        bioscom(1,'x',COM4);//send an ack
      }


     if (kbhit())
     {
        if ((in = getch()) == '\x1B')
        break;
     }
   }
   fclose(fp);
   return 0;
}

Sender file on laptop with USB port:

#include <stdio.h>
#include <bios.h>
#include <conio.h>
#include<dos.h>
#include<stdlib.h>
#include<time.h>

#define RTS 0x02
#define COM1       0
#define COM4       3
#define CURRCOM   COM4
#define DATA_READY 0x100
#define TRUE       1
#define FALSE      0

#define SETTINGS ( 0xE0 | 0x03 | 0x00 | 0x00)

int main(void)
{
   int in, out, status, DONE = FALSE,nextfile = 1;
   char c;
   FILE *fp,*fp1;
   unsigned long count = 0,shiftcount = 0;
   clock_t start,end;

   start = clock();

   clrscr();

   fp = fopen("C:/TC/pic.jpg","rb");
   fp1 = fopen("C:/TC/pic.jpg","rb");

   fseek(fp1,0L,2);
   count = ftell(fp1) + 1;

   bioscom(0, SETTINGS, CURRCOM);

  /*  while(!feof(fp1))
    {
    c = fgetc(fp1);
    count++;
    } */


   printf("No. of Cheracters = %lu\n",count);


    bioscom(1,count,CURRCOM);

    bioscom(1,count>>8,CURRCOM);

    bioscom(1,count>>16,CURRCOM);

    bioscom(1,count>>24,CURRCOM);

   cprintf("\n... BIOSCOM [ESC] to exit ...\n");
   while (!DONE)
   {
      status = bioscom(3, 0, CURRCOM);
      if (status & DATA_READY)
      {
        out = bioscom(2,0,CURRCOM);

        if(!feof(fp))
        {
            c = fgetc(fp);
            bioscom(1,c,CURRCOM);
            putch(c);
        }
      }

     if (kbhit())
     {
        if ((in = getch()) == '\x1B')
           DONE = TRUE;
     }
   }
   fclose(fp);

   end = clock();
   printf("\nTotal time = %d\n",(end - start)/CLK_TCK);

   return 0;
}

Receiver file on laptop with serial port :

#include <stdio.h>
#include <bios.h>
#include <conio.h>
#include<time.h>

#define COM1       0
#define DATA_READY 0x100
#define TRUE       1
#define FALSE      0

#define SETTINGS ( 0xE0 | 0x03 | 0x00 | 0x00)

int main(void)
{
   int in, out, status;
   char c;
   FILE *fp;
   int y = 0,esc;
   unsigned long count=0,shiftcount1 = 0,shiftcount2 = 0,shiftcount3 = 0,shiftcount4 = 0, DONE = 1;

   clock_t start,end;

   start = clock();

   clrscr();

   fp = fopen("C:/TC/pic1.jpg","wb");

   bioscom(0, SETTINGS, COM1);
   cprintf("... BIOSCOM [ESC] to exit ...\n");

   shiftcount1 = bioscom(2,0,COM1);
   shiftcount2 = bioscom(2,0,COM1);
   shiftcount3 = bioscom(2,0,COM1);
   shiftcount4 = bioscom(2,0,COM1);

   bioscom(1,'x',COM1);

   count = shiftcount1 | (shiftcount2<<8) | (shiftcount3<<16) | (shiftcount4<<24);

   printf("shift4 = %lu\tshift3 = %lu\tshift2 = %lu\t shift1 = %lu\n",shiftcount4,shiftcount3,shiftcount2,shiftcount1);
   printf("file size = %lu\n",count);

   while (DONE < count)
   {
      status = bioscom(3, 0, COM1);
      //printf("%d",status);
      if (status & DATA_READY)
      {
        out = bioscom(2, 0, COM1);
        DONE++;
        fputc(out,fp);
        putch(out);
        bioscom(1,'x',COM1);
      }


     if (kbhit())
     {
        if ((in = getch()) == '\x1B')
           break;
     }
   }
   fclose(fp);

   end = clock();
   printf("\nTotal time = %f\n",(end - start)/CLK_TCK);

   return 0;
}

The above 4 programs behaves as, sender send a character and receives an ack for every character. I have followed this approach, bcoz other approaches were not working fine (in the sense the complete data is not sent, the amount of data sent is not judgeable, bcoz it will different every tym). when i used this approach it worked fine.

Using C# language : Below two programs are written in C# using visual studio. I have used SerilaPort class , its properties and methods for communication. Using this, am able to communicate text and xml files on both the sides successfully.Also image files with .jpg extention, can be transferred from USB to serial end withot any loss of data(successful transmission), but if i transfer from serial to usb end, am able receive image with some data loss, even with the data loss am able to see the image.

Sender file on laptop with serial port :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO.Ports;
using System.IO;
using System.Threading;

namespace Communication
{
    class Program
    {
        static void Main(string[] args)
        {

            string name;
            string message;
            StringComparer stringComparer = StringComparer.OrdinalIgnoreCase;
            //Thread readThread = new Thread(Read);


            FileStream fs = new FileStream("C:/text.xml", FileMode.Open);

            //StreamReader sr = new StreamReader(fs);

            BinaryReader br = new BinaryReader(fs);

            // Create a new SerialPort object with default settings.
            SerialPort _serialPort = new SerialPort();

            // Allow the user to set the appropriate properties.
            _serialPort.PortName = "COM1";
            _serialPort.BaudRate = 115200;
            _serialPort.Parity = Parity.None;
            _serialPort.DataBits = 8;
            _serialPort.StopBits = StopBits.One;
            _serialPort.Handshake = Handshake.None;

            // Set the read/write timeouts
            _serialPort.ReadTimeout = 500;
            _serialPort.WriteTimeout = 500;

            _serialPort.Open(); 
            bool _continue = true;
            //readThread.Start();

            int len = (int)fs.Length;
            char[] data = new char[len+1];

            br.Read(data, 0, len);

            for (int i = 0; i < len+1; i++)
            {
                _serialPort.Write(data, i, 1);
                //Console.Write(data,i,1);
            }

            br.Close();
            fs.Close();
            _serialPort.Close();

        }
    }
}

Receiver file on laptop with USB port :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO.Ports;
using System.IO;
using System.Threading;
using System.Collections;

namespace Communication
{
    class Program
    {
        static void Main(string[] args)
        {
            SerialComm comm = new SerialComm();
            comm.Init();
            comm.ReadSerial();
            comm.WriteToFile();
            comm.ResClose();
            Console.ReadKey();
        }
    }


    class SerialComm
    {
        FileStream fs = null;
        BinaryWriter file = null;
        ArrayList al = null;

        public Boolean Init()
        {
            if (fs == null)
            {
                fs = new FileStream("C:/text1.txt", FileMode.OpenOrCreate);
            }

            if (file == null)
            {
                file = new BinaryWriter(fs);
            }
            if (al == null)
            {
                al = new ArrayList();
            }

            return true;
        }

        public void ResClose()
        {
            file.Close();
            fs.Close();
        }


        public Boolean ReadSerial()
        {
            SerialPort port;
            StreamWriter sw;
            ConsoleKeyInfo ck;

            port = new SerialPort();

            port.PortName = "COM4";
            port.BaudRate = 115200;
            port.DataBits = 8;
            port.Parity = Parity.None;
            port.StopBits = StopBits.One;
            port.Handshake = Handshake.None;

            port.Open();

            port.BaseStream.Flush();
            port.DiscardInBuffer();
            int c = 1;
            while (c != 0)
            {
                c = port.ReadByte();
                al.Add((byte)c);
            }
            return true;
        }

        public void WriteToFile()
        {
            int i = 0;
            byte[] message = al.ToArray(typeof(byte)) as byte[];
            file.Write(message, 0, message.Length - 1);
        }
   }
}

Please help me.

Thanks in advance.

Answer 1

Transmission speed:

Serial ports are simple, not fast. I am assuming that you are using 230kbps which is already more than many hardware can handle. Compression is only thing that might help, but compressing already compressed data (like .mp3) won't help much.

Data loss:

Serial ports are simple, not robust. Data loss is common, and only thing you can do about it is to have protocol to detect errors on incoming frames, and have ability to retry send if there is an error.

Conclusion:

Use TCP/IP instead.

Answer 2

Way too long a question. I've found only one actual question, and that's the performance bit.

Just use Ethernet or WiFi. "Serial port" (you probably mean RS-232) speeds are low . 0.1 Mbit/second is considered fast by RS-232 standards. You clock 1200 Mbit/3600 seconds, which is 0.3 Mbit/second. That is ultra-fast. I'm in fact surprised that you achieve that, your C# program is explicitly setting the speed to 0.1 Mbit/second.