Author Topic: Test Code for Serial Port Visual Basic  (Read 14321 times)

yvytty

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Test Code for Serial Port Visual Basic
« on: April 24, 2013, 02:42:53 pm »
I am new to coding. I have been asked to write a program to send/receive data through a serial port from host/slave. This is my current working test code. I created two ports and used a virtual port emulator.

As this is my first paying job, I am wondering if I could have some critical feedback on this.

I have purchased several of your books. I really appreciate your help. Thanks.

I've taken out any code not directly related to the ports.

Imports System.IO.Ports

Class form1

    '==set and open port==
    '==not using get portname- COM1 to be used as dedicated port as spec==
    Private Sub btnReSet_Click(sender As Object, e As EventArgs) Handles btnReSet.Click

        If SerialPort1.IsOpen = False Then
            '==Open and set COM1 as host==
            Try
                '==Set COM1 as portname==
                SerialPort1.PortName = "COM1"
                '==Port settings==
                SerialPort1.BaudRate = 9600
                SerialPort1.Parity = Parity.None
                SerialPort1.StopBits = StopBits.One
                SerialPort1.DataBits = 8
                SerialPort1.ReadTimeout = 100
                '==Open port==
                SerialPort1.Open()
                rtbCom1.Text = "COM1 Ready"
                tmrPoll.Start()
            Catch ex As Exception
                rtbCom1.Text = "open error " & ex.Message
            End Try
        End If

        '==Used to test data send/rec==
        If SerialPort2.IsOpen = False Then
            Try
                SerialPort2.PortName = "COM2"
                SerialPort2.BaudRate = 9600
                SerialPort2.Parity = Parity.None
                SerialPort2.StopBits = StopBits.One
                SerialPort2.DataBits = 8
                SerialPort2.Open()
                rtbCom2.Text = "COM2 Open"

            Catch ex As Exception
                rtbCom2.Text = "open error " & ex.Message
            End Try
        End If

    End Sub

    '==CONTROL CHARACTERS- as spec==
    '==start and stop values==
    Dim STX As Byte = &H2
    Dim ETX As Byte = &H3
    '==Acknowledgment==
    Dim ACK As Byte = &H6
    '==class and address==
    Dim DeviceClass As String = "E"
    Dim DeviceAddress As String = "1"
    '==Command to read==
    Dim DeviceRead As String = "R"
    '==Command to Write==
    Dim DeviceWrite As String = "W"
    '==[[[stx(start), device class, device address, device command, register register (REG), device data(D1 D0), etx(end)]]]==
    '==array of register values, i=index==
    '==note for self==='hex15='NAK!==
    Dim REG = New String() {"22", "23", "2F", "30"}

    '==FOR ME!!test data==
    Dim D1 = New Integer() {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
    Dim D0 = New Integer() {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}

    '==data to send==
    Dim portWrite As String
    '==data to write==
    Dim portRead As String

   
    Private Sub tmrPoll_Tick(sender As Object, e As EventArgs) Handles tmrPoll.Tick

        '==FOR ME!!loop counter for testing==
        Dim i As Integer = 0
        '==timeout error counter==
        Dim j As Integer = 0

        '==Prevent unnecessary timeout errors/allow time lag for port to open==
        Do While SerialPort1.IsOpen = True And SerialPort2.IsOpen = True

            '==Loop through Register==
            For Each r In REG

                Dim portWrite As String = (STX & DeviceClass & DeviceAddress & ACK & r & i & i & ETX)

                Try
                    '==Loop Host Commands for Register==
                    SerialPort1.WriteLine(portWrite & vbCr)
                    '==Time for DataReceived Event Handlers to execute==
                    lst1.Items.Add(STX & DeviceClass & DeviceAddress & ACK & r & i & i & ETX & vbCr)

                Catch ex As Exception
                    rtbCom1.Text = "Write Error: " & ex.Message
                End Try

                Try
                    '==readline to separate data==
                    portRead = SerialPort2.ReadLine()
                    '==display data in GUI==
                    lst2.Items.Add(portRead)

                    '==Get Register Value==
                    Dim r1 As String
                    '==Slave data values==
                    Dim d As Integer

                    '==[[[STX & DeviceClass & DeviceAddress & ACK & REG1 & REG0 (REG) & D0 & D1 & ETX]]]==
                    '==2-E-1-6-r-r-X-X-3==
                    '==Get the Data Value for Individual Register==
                    r1 = portRead.Substring(4, 2)
                    '==convert data to integer, so data can be displayed graphically==
                    d = CInt(portRead.Substring(6, 2))

                    '==Display received substring values==
                    Select Case r1
                        Case Is = "22"
                            'list box until advised.
                            lst1.Items.Add(r1 & d)
                        Case Is = "23"
                            '==display data as shape==
                            shpTemp.Width = d * 2
                        Case Is = "2F"
                            shpAmp.Width = d
                        Case Is = "30"
                            shpVolt.Width = d * 3
                    End Select

                Catch ex As Exception
                    lst2.Items.Add("Read error: " & ex.Message)

                End Try

                If j > 2 Then

                    rtbCom2.Text = "Operation Aborted: 3 timeout errors."
                    '==Stop program if 3 timeout errors- as spec/closed port should terminate Do while==
                    SerialPort1.Close()
                    rtbCom1.Text = "port closed - Operation Aborted: 3 timeout errors."
                    ' shpAmp.Width = -1
                    shpTemp.Width = -1
                    shpVolt.Width = -1
                    tmrPoll.Stop()
                    Exit Do

                End If
            Next
            i += 1
            If i > 9 Then
                i = 0
            End If
        Loop

    End Sub


End Class
About Programming - I've never taken on an endeavour that totally absorbs and challenges me; yet can make me feel like a simpleton simultaneously.

yvytty

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Re: Test Code for Serial Port Visual Basic
« Reply #1 on: April 24, 2013, 03:06:30 pm »
Actually, I my timeout count loop is not working.. just tested it using

                Dim portWrite As String = (STX & DeviceClass & DeviceAddress & ACK & r & i & i) ' & ETX)

                Try
                    '==Loop Host Commands for Register==
                    SerialPort1.Write(portWrite) ' & vbCr)
About Programming - I've never taken on an endeavour that totally absorbs and challenges me; yet can make me feel like a simpleton simultaneously.

yvytty

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Re: Test Code for Serial Port Visual Basic
« Reply #2 on: April 24, 2013, 03:08:39 pm »
oh I'm so stupid, forgot to add j+=1 !!
About Programming - I've never taken on an endeavour that totally absorbs and challenges me; yet can make me feel like a simpleton simultaneously.

Jan Axelson

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Re: Test Code for Serial Port Visual Basic
« Reply #3 on: April 24, 2013, 06:09:21 pm »
If the application is doing what you intended, you've done the hard part!

If your edition of Visual Studio supports it, you can do Build > Run Code Analysis on Solution.

yvytty

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Re: Test Code for Serial Port Visual Basic
« Reply #4 on: April 24, 2013, 09:23:39 pm »
Thanks Jan.. I did and no problem.. I'm just scared, as I can only test it on a virtual port emulator ..
About Programming - I've never taken on an endeavour that totally absorbs and challenges me; yet can make me feel like a simpleton simultaneously.

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Re: Test Code for Serial Port Visual Basic
« Reply #5 on: April 24, 2013, 09:47:47 pm »
If you lack serial ports, use two USB/serial converters and a null-modem connector.

yvytty

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Re: Test Code for Serial Port Visual Basic
« Reply #6 on: April 24, 2013, 09:49:41 pm »
thanks
About Programming - I've never taken on an endeavour that totally absorbs and challenges me; yet can make me feel like a simpleton simultaneously.

yvytty

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Re: Test Code for Serial Port Visual Basic
« Reply #7 on: May 04, 2013, 11:46:55 pm »
Hi again,

What is the best way to display the data more frequently?

Cheers,
Yvette
About Programming - I've never taken on an endeavour that totally absorbs and challenges me; yet can make me feel like a simpleton simultaneously.

Jan Axelson

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Re: Test Code for Serial Port Visual Basic
« Reply #8 on: May 05, 2013, 04:36:49 pm »
Add a handler that executes on a DataReceived event. See my COM port terminal example:

http://www.lvr.com/serport.htm#my_example_code

yvytty

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Re: Test Code for Serial Port Visual Basic
« Reply #9 on: May 07, 2013, 04:11:15 am »
Thanks Jan,

Yes, I like that code and have seen it before (I've read some of your books :-)

What I am wondering though.. is I experimented and using writieline/readline it seemed to display the data more regularly, as did playing with the loops.. Is there another way of pacing how frequently the data is read and displayed? Otherwise, what is the point of polling?
Please bear with me, I'm a beginner and trying to fully understand these things.

Cheers,
Yvette
About Programming - I've never taken on an endeavour that totally absorbs and challenges me; yet can make me feel like a simpleton simultaneously.

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Re: Test Code for Serial Port Visual Basic
« Reply #10 on: May 07, 2013, 12:47:39 pm »
I'm not sure what you're asking. You can use events or you can attempt to read periodically. Which read method you use will determine whether returning data requires a LF/CR. You can also set the minimum number of bytes/characters to read. See the SerialPort class documentation for more info.

yvytty

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Re: Test Code for Serial Port Visual Basic
« Reply #11 on: May 07, 2013, 12:55:06 pm »
I'm using the code I posted above, so it's with a timer.. which is why I was confused by your answer.
It just doesn't seem to update the display (data received) as frequently as it should. If you look at my code, you may know why...
About Programming - I've never taken on an endeavour that totally absorbs and challenges me; yet can make me feel like a simpleton simultaneously.

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Re: Test Code for Serial Port Visual Basic
« Reply #12 on: May 07, 2013, 01:30:00 pm »
ReadLine won't return data until receiving a line termination. Other than that, try to isolate the problem by (1) defining it: how frequently do you expect the display to update and how frequently is it being updated? and (2) sending test data and monitoring what's received and displayed, etc.

yvytty

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Re: Test Code for Serial Port Visual Basic
« Reply #13 on: May 07, 2013, 01:36:58 pm »
If I have built in line terminations, that should be ok? is CR considered a line termination for readline (pardon my ignorance- I just want to be sure) I will take the steps you suggested.
About Programming - I've never taken on an endeavour that totally absorbs and challenges me; yet can make me feel like a simpleton simultaneously.

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Re: Test Code for Serial Port Visual Basic
« Reply #14 on: May 07, 2013, 04:23:57 pm »
See the environment.newline property.