How can i display data from a microcontroller to PC using Serialport

I try the codes in the similar situation, but it is unstable,

I remove this line:

//textData = "55,43,23,12,32,22,12,44,";    // example string - i cannot get anything from my port...

sometimes it work, sometime I got an error message

the error message is about "textData" in this function:

private void SetTextToTextboxes(string textData)

it said that the textData was null,


how to solve this problem?


Thank you very much!

Use something like this:

if (separatedData.Length == 8)

{

         this.Text = "Data Ok";

         if (TimeToSaveData())// timeout checking

         {

                SaveTemperatureToDB(separatedData);

                m_LastSaveTime = DateTime.Now;

         }

And function:

DateTime m_LastSaveTime;

private bool TimeToSaveData()

{

         return m_LastSaveTime.AddMinutes(3) < DateTime.Now;                                   

}

Sure you can!

I can guess that you want to store all data in DB – for future statistic or something…

:)

If so, you can do it in same delegate – that inserts data to check boxes.

The function for this should be like:

if (separatedData.Length == 8)

{

                this.Text = "Data Ok";

                SaveTemperatureToDB(separatedData);// function call

                …….

private void SaveTemperatureToDB(string[] separatedData)

{

         SqlConnection dbConnect = new SqlConnection("conn string");

         dbConnect.Open();

         string sSql = "INSERT INTO  Temeratures ([col_temp1] , [col_temp2] ,[col_temp3] )   VALUES   (";

         for (int iii = 0; iii < separatedData.Length; iii++)

         {

                if (iii != separatedData.Length - 1) // not last element

                {

                                sSql += separatedData[iii] + ",";

                }

                else // last element

                {

                                sSql += separatedData[iii] + ")";

                }

         }

         SqlCommand sqlCommand = new SqlCommand(sSql,dbConnect);

         sqlCommand.ExecuteNonQuery();

         dbConnect.Close();                     

}

This is example for MS-SQL client, but for every other will be same prinsip.

I have written the simplest example of dynamic query building – without protection and optimisations (that can be implemented using sql params and exeption catching) and so on…

Also – you should change the table name and colums names in sSql string – I do not know exact names in your DB.

Aha, now it is more clear…..

So, try this code :

string m_serialData; // data needs to besaved beetween events

bool m_readEnd = false;

private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)

{

      char dataChar = ' ';

      while (serialPort1.BytesToRead > 0)

      {

                   dataChar = (char)serialPort1.ReadChar();

                   if (dataChar != 'N')// reading only beetween 'N' ..... 'N'

                   {

                            m_serialData += dataChar; // collecting the data

                   }

                   else

                   {

                            m_readEnd = true;

                            break;

                   }

      }

      if (m_readEnd) // next 'N' found - needs to send collected data

      {                       

                   SetTextToTextboxes(m_serialData);//end reading  send string of data to main thread

                   m_serialData = ""; // data sent, ready for next

                   m_readEnd = false;                                                          

      }

}

delegate void SetTextToView(string textData);

private void SetTextToTextboxes(string textData)

{

      if (this.InvokeRequired)

      {

                   SetTextToView tempDelegate = new SetTextToView(SetTextToTextboxes);

                   this.Invoke(tempDelegate, new object[] { textData });

      }

      else

      {

                   //textData = "55,43,23,12,32,22,12,44,";    // example string - i cannot get anything from my port...

                   // now string contains only numbers and commas

                   string[] separatedData = textData.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries); // now string contains only numbers and commas

                   if (separatedData.Length == 8)

                   {

                            this.Text = "Data Ok";

                            textBox1.Text = separatedData[0]; // this is more optimal for this task

                            textBox2.Text = separatedData[1]; // instead common solution

                            textBox3.Text = separatedData[2]; // to set all needed data in one delegate

                            textBox4.Text = separatedData[3];

                            textBox5.Text = separatedData[4];

                            textBox6.Text = separatedData[5];

                            textBox7.Text = separatedData[6];

                            textBox8.Text = separatedData[7];

                   }

                   else

                   {

                            this.Text = "Data error";

                   }

      }

}

I have commented important places, so it will (may ) help you to implement the idea in your progam.

So, "N" is also separator. It is a surprise for me. :-)

This code:

private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)

{

      string serialData = "";

      //while (serialPort1.BytesToRead> 0)

      //{

      //    serialData += (char)serialPort1.ReadChar();

      //}

      serialData = "N55,43,23,12,32,22,12,44,N55,43,23,12,32,22,12,44,N55,43,23,12,32,22,12,44";                // example string - i cannot get anything from my port...

      string[] dataRows = serialData.Split(new char [] {'N'}, StringSplitOptions.RemoveEmptyEntries);

      if (dataRows.Length > 0)

      {

                string[] separatedData = dataRows[0].Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries); // only first row wil be displayed...

                if (separatedData.Length == 8)// data validation

                {

                                SetText(textBox1, separatedData[0]);// this is not best kind of binding

                                SetText(textBox2, separatedData[1]);// but will work

                                SetText(textBox3, separatedData[2]);

                                SetText(textBox4, separatedData[3]);

                                SetText(textBox5, separatedData[4]);

                                SetText(textBox6, separatedData[5]);

                                SetText(textBox7, separatedData[6]);

                                SetText(textBox8, separatedData[7]);

                }

                else

                {

                                SetText(this, "Error in received data"); // data is not valid

                }

      }

}

can show only first row in received data.

I do not (cannot guess) know, what you want to do with other rows (we have only 8 textboxes on form)….

May be you want to show stream of real time data - changes every second or something.

You problem is that event of serial port rises in other thread.

Here is example:

private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)

{

                string serialData = "";

                //while (serialPort1.BytesToRead> 0)

                //{

                //    serialData += (char)serialPort1.ReadChar();

                //}

                serialData = "N55,43,23,12,32,22,12,44";      // example string - i cannot get anything from my port...

                string [] separatedData = serialData.Split(','); // may be here you needs more smart splitting

                if (separatedData.Length == 8)// data validation

                {

                                SetText(textBox1, separatedData[0]);// this is not best kind of binding

                                SetText(textBox2, separatedData[1]);// but will work

                                SetText(textBox3, separatedData[2]);

                                SetText(textBox4, separatedData[3]);

                                SetText(textBox5, separatedData[4]);

                                SetText(textBox6, separatedData[5]);

                                SetText(textBox7, separatedData[6]);

                                SetText(textBox8, separatedData[7]);

                }

                else

                {

                                SetText(this, "Error in received data"); // data is not valid

                }

}

delegate void SetTextToControl(Control viewControl, string textData);

private void SetText(Control viewControl, string textData)

{

                if (viewControl.InvokeRequired)

                {

                                SetTextToControl tempDelegate = new SetTextToControl(SetText);

                                viewControl.Invoke(tempDelegate, new object[] { viewControl, textData });

                }

                else

                {

                                viewControl.Text = textData;

                }

}

This data  should be received as byte array (byte [] mcResivedData) and

converted to string by following code:

string resultString = "";

byte[] mcResivedData =  { 55, 23, 12, 34, 42, 33, 22, 23, 55, 23, 12, 34, 42, 33, 22, 23 };

foreach (byte rByte in mcResivedData)

{

// here you can add any checking and logic - how you want to se (or dont) any byte with spesific value

                   resultString += (char)rByte;

}

this.Text = resultString;

*if amount of data is big (more than 1000 bytes at onse) better use StringBuilder instead string.