10-bit serial data turned into 8-bit?

Hi guys,

I made a simple Arduino serial program to send to my PC via COM Port looking like this:

C Code:

int byteNumber = 80;
 
const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to
int sensorValue = 0;        // value read from the pot
int a = 0;
int i = 0;
 
void setup() {
 
   Serial.begin(9600);
 
   
}
 
void loop() {
   
   sensorValue = analogRead(analogInPin);
   // Note: Number of bytes sent is upper limit + 1
   // If 10 bytes is desired, then it has to be i = 9
   
   
   for(i=0; i<= byteNumber - 1; i++){
     sensorValue = analogRead(analogInPin);
     Serial.write(sensorValue);
   }
   
   
   delay(100);
 
 
   
}

Here's how it looked like when it's transmitting above 1000 values in the serial terminal:

Attachment 184912

As you can see, it's basically 10-bit values.

Here's the code on the VB side:

Code:

---

Imports System
Imports System.IO.Ports
Imports System.Threading
Imports System.Text
Imports System.Windows.Forms.DataVisualization.Charting

Public Class Form1

    Public myComPort As New SerialPort
    Dim buffer As String
    Dim count As Integer = 0
    Dim DataBuffer As DataTable
    Dim dr As DataRow
    Public DataSetBuffer As DataSet
    Dim DataTableBuffer As DataTable


    Dim state As Boolean = False

    Dim cycle As Integer = 1
    Dim List1, List2, List3, List4, List5, List6, List7, List8, List9, List10 As List(Of Integer)
    Dim cutoff1, cutoff2, cutoff3, cutoff4 As Integer


    '///////////////////////////////////////////////////
    ' How many bytes are you receiving per packet?
    Dim Byte_number = 80
    '///////////////////////////////////////////////////
    '///////////////////////////////////////////////////




    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button_Connect.Click



        myComPort.PortName = "COM17"
        myComPort.BaudRate = 9600
        myComPort.Parity = Parity.None
        myComPort.DataBits = 8
        myComPort.StopBits = StopBits.One
        myComPort.ReadTimeout = Nothing
        myComPort.DtrEnable = True
        myComPort.RtsEnable = True

        myComPort.Open()

        AddHandler myComPort.DataReceived, SerialDataReceivedEventHandler

    End Sub

    ' Define a delegate class to handle DataReceived events.
    Friend Delegate Sub SerialDataReceivedEventHandlerDelegate(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)

    ' Create an instance of the delegate.
    Private SerialDataReceivedEventHandler As New SerialDataReceivedEventHandler(AddressOf DataReceived)

    Public Sub DataReceived(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)


        'On Error Resume Next

        Do

            Dim ReceiveBuf() As Byte = New Byte() {}

            'MsgBox(ReceiveBuf.Count)

            Array.Resize(ReceiveBuf, Byte_number)
            myComPort.Read(ReceiveBuf, 0, Byte_number)

            UpdateGrid(ReceiveBuf)

        Loop While myComPort.BytesToRead <> 0


    End Sub

    Public Function CreateList(bytes_input As Byte()) As List(Of Integer)
        Dim x As New List(Of Integer)
        For Each b As Byte In bytes_input
            x.Add(CInt(b))
        Next
        Return x
    End Function

    Public Sub CutoffDetector(ByVal buffer As List(Of Integer), ByVal Display As Label, ByRef Cutoff As Integer)

        Dim cutoff_region1 = 0
        Dim cutoff_index1 = 0
        For Each value In buffer
            If value = 0 Then
                cutoff_region1 += 1
            End If

            If value <> 0 Then
                cutoff_region1 = 0
            End If

            If cutoff_region1 > 0 Then
                cutoff_index1 = buffer.IndexOf(value)
                Exit For
            End If
        Next


        Cutoff = cutoff_index1
        Display.Text = cutoff_index1

        'Return cutoff_index1


    End Sub


    Public Sub Recombiner(ByRef List As List(Of Integer), ByRef cutoff_index1 As Integer, ByRef cutoff_index2 As Integer, ByRef cutoff_index3 As Integer)

        List = New List(Of Integer)
        For b = 0 To cutoff_index1 - 1
            List.Add(List1(b))
        Next

        For b = 0 To cutoff_index2 - 1
            List.Add(List2(b))
        Next

        For b = 0 To cutoff_index3 - 1
            List.Add(List3(b))
        Next

    End Sub

    Public Sub UpdateGrid(ByVal bytes_Input As Byte())

        'On Error Resume Next
        Dim total As Integer

        If Me.InvokeRequired Then
            Me.Invoke(New Action(Of Byte())(AddressOf UpdateGrid), bytes_Input)

        Else


            Select Case cycle
                Case 1

                    List1 = CreateList(bytes_Input)
                    CutoffDetector(List1, Label1a, cutoff1)


                Case 2

                    List2 = CreateList(bytes_Input)
                    CutoffDetector(List2, Label2a, cutoff2)



                Case 3

                    List3 = CreateList(bytes_Input)
                    CutoffDetector(List3, Label3a, cutoff3)

                    cycle = 0
                    total = cutoff1 + cutoff2 + cutoff3



                    If total = Byte_number Then

                        Total2.Text = cutoff1 + cutoff2 + cutoff3
                        Recombiner(List4, cutoff1, cutoff2, cutoff3)


                        Dim y = 1


                        DataTableBuffer = New DataTable()
                        DataTableBuffer.Columns.Add("Time (ms)")
                        DataTableBuffer.Columns.Add("Volts (V)")



                        Dim a = 0
                        For Each value As Byte In List4

                            dr = DataTableBuffer.NewRow()
                            dr("Time (ms)") = a
                            dr("Volts (V)") = value
                            DataTableBuffer.Rows.Add(dr)

                            a = a + 1
                        Next

                        DataGridView1.DataSource = DataTableBuffer
                        Charter(Chart1, DataTableBuffer, "ADC Volts")



                    End If


            End Select

            cycle += 1

            Application.DoEvents()

        End If




    End Sub






    Public Sub Charter(x As Chart, dt As DataTable, Series_name As String)
        x.Series.Clear()
        Dim Test As Series = x.Series.Add(Series_name)
        Test.Name = Series_name
        Test.ChartType = SeriesChartType.FastLine
        x.Series(Series_name).Color = Color.LimeGreen
        x.Series(Series_name).BorderWidth = 2.0
        x.Series(Series_name).XValueMember = "Time (ms)"
        x.Series(Series_name).YValueMembers = "Volts (V)"
        x.Series(0)("LineTension") = 10
        'x.ChartAreas(0).AxisY.Maximum = 160
        'x.ChartAreas(0).AxisY.Minimum = 30

        x.ChartAreas(0).AxisY.Maximum = 256
        x.ChartAreas(0).AxisY.Minimum = 0
        x.ChartAreas(0).AxisX.Interval = Byte_number / 10

        x.ChartAreas(0).AxisX.Maximum = Byte_number

        x.DataSource = dt
    End Sub

    Private Sub Arm_Click(sender As Object, e As EventArgs) Handles Arm.Click
        state = True
    End Sub
End Class

---

And the GUI looks like the following:

Attachment 184913

(Bear in mind that the two screenshots are not done simultaneously. It's because for the Arduino code, I have to use "Serial.println" to display the values and later switch to "Serial.write" to write the values to the serial port.)

And it looks like it only recorded up to 255 in decimal values maximum.

It seems like it went through some resolution loss because the values which fluctuate are proportional, rather than being cut off.

Is it possible to retain the extra two bits?

Thanks!
Vizier87

This shows my approach to SerialPort programming. My guess is that you are sending two bytes that represent the 10 bit value.

Code:

---

Imports System.IO.Ports

Public Class Form1

    Private WithEvents TheSP As New IO.Ports.SerialPort
    Private HaveData As New Threading.AutoResetEvent(False)
    Private InData As New Concurrent.ConcurrentQueue(Of List(Of Byte))
    Private ProcDataTask As Task

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
        ProcDataTask = Task.Run(Sub() ProcData()) 'start a background thread to process data
    End Sub

    Private Sub Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown
        RichTextBox1.Clear()
        OpenSP()
    End Sub

    Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
        Try
            If TheSP.IsOpen Then
                TheSP.Close()
            End If
            TheSP.Dispose()
        Catch ex As Exception
            Stop
        End Try
    End Sub

    Private Sub _DataReceived(sender As Object,
                                        e As IO.Ports.SerialDataReceivedEventArgs) Handles TheSP.DataReceived
        'do as little as possible in the handler
        ' .BytesToRead may not be what you expect
        Dim readBuf(TheSP.BytesToRead - 1) As Byte 'buffer for bytes
        Try
            '.Read returns how many read
            Dim br As Integer = TheSP.Read(readBuf, 0, readBuf.Length) 'read bytes
            'queue up the data received
            InData.Enqueue(readBuf.Take(br).ToList)
            HaveData.Set() ' data to process signal
            '
            If br <> readBuf.Length Then
                'todo Didn't read all available
            End If
        Catch ex As Exception
            'todo
        End Try
    End Sub

    Private Sub ProcData()
        'process the data
        Dim AllDataQ As New List(Of Byte)
        Do
            HaveData.WaitOne() 'wait for HaveData.Set in Handler
            'Debug.WriteLine("")
            'process the queue
            Dim OneBuf As List(Of Byte)
            While Not InData.IsEmpty
                If InData.TryDequeue(OneBuf) Then 'get some data
                    AllDataQ.AddRange(OneBuf)
                    'Debug.WriteLine(OneBuf.Count)
                Else
                    HaveData.WaitOne(1)
                End If
            End While

            '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
            ' at this point the protocol of the device is
            '  enforced.
            '
            'This sample just empties the buffer
            '  show each received byte as hex.
            '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
            If AllDataQ.Count > 0 Then
                Dim sb As New System.Text.StringBuilder
                sb.AppendLine()
                For Each b As Byte In AllDataQ
                    sb.Append(b.ToString("X2"))
                Next
                sb.AppendLine()
                AllDataQ.Clear()
                '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
                'UI Stuff
                Me.Invoke(Sub()
                              RichTextBox1.AppendText(sb.ToString)
                              RichTextBox1.ScrollToCaret()
                          End Sub)
                '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
            End If
        Loop
    End Sub

    Private Sub OpenSP()
        Dim t As Task
        t = Task.Run(Sub()
                        If Not TheSP.IsOpen Then
                            'Modify settings as needed <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            TheSP.PortName = "COM1"
                            TheSP.BaudRate = 115200 '  19200 ' 
                            TheSP.DataBits = 8
                            TheSP.Parity = Parity.None
                            TheSP.StopBits = StopBits.One

                            'other settings as needed - consider speed and max size to determine settings  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            TheSP.ReceivedBytesThreshold = 1 'one is the default, recommend no change unless absolutely needed
                            TheSP.ReadTimeout = 1000 'default is infinite if not set
                            TheSP.WriteTimeout = 1000 'default is infinite if not set
                            TheSP.ReadBufferSize = 1024 * 4 'Windows-created input buffer 4096 is default, change if needed
                            TheSP.WriteBufferSize = 1024 * 2  'Windows-created output buffer 2048 is default, change if needed

                            'this setting is informational only.  the code only reads bytes  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            'if the device is sending strings recommend setting this to match encoding device is using  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            'if the application is writing strings this must match devices encoding                    <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            TheSP.Encoding = System.Text.Encoding.GetEncoding(28591) 'default is 7 bit ascii, this is an 8 bit flavor of asciii
                            Try
                                TheSP.Open()
                                'some devices require the following
                                TheSP.DtrEnable = True 'only after Open. may cause multiple PinChanged events
                                'SerialPort Open
                            Catch ex As Exception
                                Debug.WriteLine(ex.Message)
                            End Try
                        End If
                    End Sub)
    End Sub
End Class

---

Quote:

---

Originally Posted by dbasnett

This shows my approach to SerialPort programming. My guess is that you are sending two bytes that represent the 10 nit value.

Code:

---

Imports System.IO.Ports

Public Class Form1

    Private WithEvents TheSP As New IO.Ports.SerialPort
    Private HaveData As New Threading.AutoResetEvent(False)
    Private InData As New Concurrent.ConcurrentQueue(Of List(Of Byte))
    Private ProcDataTask As Task

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
        ProcDataTask = Task.Run(Sub() ProcData()) 'start a background thread to process data
    End Sub

    Private Sub Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown
        RichTextBox1.Clear()
        OpenSP()
    End Sub

    Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
        Try
            If TheSP.IsOpen Then
                TheSP.Close()
            End If
            TheSP.Dispose()
        Catch ex As Exception
            Stop
        End Try
    End Sub

    Private Sub _DataReceived(sender As Object,
                                        e As IO.Ports.SerialDataReceivedEventArgs) Handles TheSP.DataReceived
        'do as little as possible in the handler
        ' .BytesToRead may not be what you expect
        Dim readBuf(TheSP.BytesToRead - 1) As Byte 'buffer for bytes
        Try
            '.Read returns how many read
            Dim br As Integer = TheSP.Read(readBuf, 0, readBuf.Length) 'read bytes
            'queue up the data received
            InData.Enqueue(readBuf.Take(br).ToList)
            HaveData.Set() ' data to process signal
            '
            If br <> readBuf.Length Then
                'todo Didn't read all available
            End If
        Catch ex As Exception
            'todo
        End Try
    End Sub

    Private Sub ProcData()
        'process the data
        Dim AllDataQ As New List(Of Byte)
        Do
            HaveData.WaitOne() 'wait for HaveData.Set in Handler
            'Debug.WriteLine("")
            'process the queue
            Dim OneBuf As List(Of Byte)
            While Not InData.IsEmpty
                If InData.TryDequeue(OneBuf) Then 'get some data
                    AllDataQ.AddRange(OneBuf)
                    'Debug.WriteLine(OneBuf.Count)
                Else
                    HaveData.WaitOne(1)
                End If
            End While

            '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
            ' at this point the protocol of the device is
            '  enforced.
            '
            'This sample just empties the buffer
            '  show each received byte as hex.
            '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
            If AllDataQ.Count > 0 Then
                Dim sb As New System.Text.StringBuilder
                sb.AppendLine()
                For Each b As Byte In AllDataQ
                    sb.Append(b.ToString("X2"))
                Next
                sb.AppendLine()
                AllDataQ.Clear()
                '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
                'UI Stuff
                Me.Invoke(Sub()
                              RichTextBox1.AppendText(sb.ToString)
                              RichTextBox1.ScrollToCaret()
                          End Sub)
                '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
            End If
        Loop
    End Sub

    Private Sub OpenSP()
        Dim t As Task
        t = Task.Run(Sub()
                        If Not TheSP.IsOpen Then
                            'Modify settings as needed <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            TheSP.PortName = "COM1"
                            TheSP.BaudRate = 115200 '  19200 ' 
                            TheSP.DataBits = 8
                            TheSP.Parity = Parity.None
                            TheSP.StopBits = StopBits.One

                            'other settings as needed - consider speed and max size to determine settings  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            TheSP.ReceivedBytesThreshold = 1 'one is the default, recommend no change unless absolutely needed
                            TheSP.ReadTimeout = 1000 'default is infinite if not set
                            TheSP.WriteTimeout = 1000 'default is infinite if not set
                            TheSP.ReadBufferSize = 1024 * 4 'Windows-created input buffer 4096 is default, change if needed
                            TheSP.WriteBufferSize = 1024 * 2  'Windows-created output buffer 2048 is default, change if needed

                            'this setting is informational only.  the code only reads bytes  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            'if the device is sending strings recommend setting this to match encoding device is using  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            'if the application is writing strings this must match devices encoding                    <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
                            TheSP.Encoding = System.Text.Encoding.GetEncoding(28591) 'default is 7 bit ascii, this is an 8 bit flavor of asciii
                            Try
                                TheSP.Open()
                                'some devices require the following
                                TheSP.DtrEnable = True 'only after Open. may cause multiple PinChanged events
                                'SerialPort Open
                            Catch ex As Exception
                                Debug.WriteLine(ex.Message)
                            End Try
                        End If
                    End Sub)
    End Sub
End Class

---

---

Oh wow thanks for your snippet! Ok lemme try this one out and I'll update in a bit.

Vizier87