Serial Port Timer

C

cmdolcet69

This code below write a serial command to the com port then read the
results and disaplays it into the label1.text property when
button1_click event is triggered. I think what is going on is that the
ocp.read is on a timer and reads char by char. How can i change this
code so that the read reads the whole result and not char by char?




Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Me.Label1.Text = String.Empty
Try
' Enable the timer.
' Write an user specified Command to the Port.
oCP.Write("[REQ]")
WriteMessage("") ', True)

Catch ex As Exception
' Warn the user.
MessageBox.Show("Unable to write to comm port")
Finally
'TextBox1.Text = ""
'TextBox1.Focus()
End Try
End Sub

Private Sub tmrRead_Tick(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles tmrRead.Tick
Try
' As long as there is information, read one byte at a time
and
' output it.
While (oCP.Read(1) <> -1)
' Write the output to the screen.
WriteMessage(Chr(oCP.InputStream(0))) ', False)
End While
Catch exc As Exception
' An exception is raised when there is no information to
read.
' Don't do anything here, just let the exception go.
End Try
End Sub


' This subroutine writes a message to the txtStatus TextBox.
Private Sub WriteMessage(ByVal message As String)

' Me.TextBox2.Text += message + vbCrLf
Me.Label1.Text += message
' TextBox2.SelectionStart = TextBox2.Text.Length
End Sub




' This function returns an integer specifying the number of bytes
' read from the Comm Port. It accepts a parameter specifying the
number
' of desired bytes to read.
Public Function Read(ByVal Bytes2Read As Integer) As Integer
Dim iReadChars, iRc As Integer

' If Bytes2Read not specified uses Buffersize
If Bytes2Read = 0 Then Bytes2Read = miBufferSize
If mhRS = -1 Then
Throw New ApplicationException( _
"Please initialize and open port before using this
method")
Else
' Get bytes from port
Try
' Purge buffers
'PurgeComm(mhRS, PURGE_RXCLEAR Or PURGE_TXCLEAR)
' Creates an event for overlapped operations
If meMode = Mode.Overlapped Then
pHandleOverlappedRead(Bytes2Read)
Else
' Non overlapped mode
ReDim mabtRxBuf(Bytes2Read - 1)
iRc = ReadFile(mhRS, mabtRxBuf, Bytes2Read,
iReadChars, Nothing)
If iRc = 0 Then
' Read Error
Throw New ApplicationException( _
"ReadFile error " & iRc.ToString)
Else
' Handles timeout or returns input chars
If iReadChars < Bytes2Read Then
Throw New IOTimeoutException("Timeout
error")
Else
mbWaitOnRead = True
Return (iReadChars)
End If
End If
End If
Catch Ex As Exception
' Others generic erroes
Throw New ApplicationException("Read Error: " &
Ex.Message, Ex)
End Try
End If
End Function
 
M

Miro

I have played with the serial port but What I used was by the event.
I did not use a timer.

I dont know if this is relevant for you or not?


Private Sub ListeningSerialPort_DataReceived(ByVal sender As System.Object, ByVal e As
System.IO.Ports.SerialDataReceivedEventArgs) Handles ListeningSerialPort.DataReceived

Dim ReceivingText As String = ""
ReceivingText = ListeningSerialPort.ReadLine


I played with this to hook a barcode scanner and throw the readings into a text box.

Miro

This code below write a serial command to the com port then read the
results and disaplays it into the label1.text property when
button1_click event is triggered. I think what is going on is that the
ocp.read is on a timer and reads char by char. How can i change this
code so that the read reads the whole result and not char by char?




Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Me.Label1.Text = String.Empty
Try
' Enable the timer.
' Write an user specified Command to the Port.
oCP.Write("[REQ]")
WriteMessage("") ', True)

Catch ex As Exception
' Warn the user.
MessageBox.Show("Unable to write to comm port")
Finally
'TextBox1.Text = ""
'TextBox1.Focus()
End Try
End Sub

Private Sub tmrRead_Tick(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles tmrRead.Tick
Try
' As long as there is information, read one byte at a time
and
' output it.
While (oCP.Read(1) <> -1)
' Write the output to the screen.
WriteMessage(Chr(oCP.InputStream(0))) ', False)
End While
Catch exc As Exception
' An exception is raised when there is no information to
read.
' Don't do anything here, just let the exception go.
End Try
End Sub


' This subroutine writes a message to the txtStatus TextBox.
Private Sub WriteMessage(ByVal message As String)

' Me.TextBox2.Text += message + vbCrLf
Me.Label1.Text += message
' TextBox2.SelectionStart = TextBox2.Text.Length
End Sub




' This function returns an integer specifying the number of bytes
' read from the Comm Port. It accepts a parameter specifying the
number
' of desired bytes to read.
Public Function Read(ByVal Bytes2Read As Integer) As Integer
Dim iReadChars, iRc As Integer

' If Bytes2Read not specified uses Buffersize
If Bytes2Read = 0 Then Bytes2Read = miBufferSize
If mhRS = -1 Then
Throw New ApplicationException( _
"Please initialize and open port before using this
method")
Else
' Get bytes from port
Try
' Purge buffers
'PurgeComm(mhRS, PURGE_RXCLEAR Or PURGE_TXCLEAR)
' Creates an event for overlapped operations
If meMode = Mode.Overlapped Then
pHandleOverlappedRead(Bytes2Read)
Else
' Non overlapped mode
ReDim mabtRxBuf(Bytes2Read - 1)
iRc = ReadFile(mhRS, mabtRxBuf, Bytes2Read,
iReadChars, Nothing)
If iRc = 0 Then
' Read Error
Throw New ApplicationException( _
"ReadFile error " & iRc.ToString)
Else
' Handles timeout or returns input chars
If iReadChars < Bytes2Read Then
Throw New IOTimeoutException("Timeout
error")
Else
mbWaitOnRead = True
Return (iReadChars)
End If
End If
End If
Catch Ex As Exception
' Others generic erroes
Throw New ApplicationException("Read Error: " &
Ex.Message, Ex)
End Try
End If
End Function
Click to expand...
 
C

cmdolcet69

I have played with the serial port but What I used was by the event.
I did not use a timer.

I dont know if this is relevant for you or not?

Private Sub ListeningSerialPort_DataReceived(ByVal sender As System.Object, ByVal e As
System.IO.Ports.SerialDataReceivedEventArgs) Handles ListeningSerialPort.DataReceived

Dim ReceivingText As String = ""
ReceivingText = ListeningSerialPort.ReadLine

I played with this to hook a barcode scanner and throw the readings into a text box.

Miro


This code below write a serial command to the com port then read the
results and disaplays it into the label1.text property when
button1_click event is triggered. I think what is going on is that the
ocp.read is on a timer and reads char by char. How can i change this
code so that the read reads the whole result and not char by char?
Click to expand...
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Me.Label1.Text = String.Empty
Try
' Enable the timer.
' Write an user specified Command to the Port.
oCP.Write("[REQ]")
WriteMessage("") ', True)
Click to expand...
Catch ex As Exception
' Warn the user.
MessageBox.Show("Unable to write to comm port")
Finally
'TextBox1.Text = ""
'TextBox1.Focus()
End Try
End Sub
Click to expand...
Private Sub tmrRead_Tick(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles tmrRead.Tick
Try
' As long as there is information, read one byte at a time
and
' output it.
While (oCP.Read(1) <> -1)
' Write the output to the screen.
WriteMessage(Chr(oCP.InputStream(0))) ', False)
End While
Catch exc As Exception
' An exception is raised when there is no information to
read.
' Don't do anything here, just let the exception go.
End Try
End Sub
Click to expand...
' This subroutine writes a message to the txtStatus TextBox.
Private Sub WriteMessage(ByVal message As String)
Click to expand...
' Me.TextBox2.Text += message + vbCrLf
Me.Label1.Text += message
' TextBox2.SelectionStart = TextBox2.Text.Length
End Sub
Click to expand...
' This function returns an integer specifying the number of bytes
' read from the Comm Port. It accepts a parameter specifying the
number
' of desired bytes to read.
Public Function Read(ByVal Bytes2Read As Integer) As Integer
Dim iReadChars, iRc As Integer
Click to expand...
' If Bytes2Read not specified uses Buffersize
If Bytes2Read = 0 Then Bytes2Read = miBufferSize
If mhRS = -1 Then
Throw New ApplicationException( _
"Please initialize and open port before using this
method")
Else
' Get bytes from port
Try
' Purge buffers
'PurgeComm(mhRS, PURGE_RXCLEAR Or PURGE_TXCLEAR)
' Creates an event for overlapped operations
If meMode = Mode.Overlapped Then
pHandleOverlappedRead(Bytes2Read)
Else
' Non overlapped mode
ReDim mabtRxBuf(Bytes2Read - 1)
iRc = ReadFile(mhRS, mabtRxBuf, Bytes2Read,
iReadChars, Nothing)
If iRc = 0 Then
' Read Error
Throw New ApplicationException( _
"ReadFile error " & iRc.ToString)
Else
' Handles timeout or returns input chars
If iReadChars < Bytes2Read Then
Throw New IOTimeoutException("Timeout
error")
Else
mbWaitOnRead = True
Return (iReadChars)
End If
End If
End If
Catch Ex As Exception
' Others generic erroes
Throw New ApplicationException("Read Error: " &
Ex.Message, Ex)
End Try
End If
End Function- Hide quoted text -
Click to expand...

- Show quoted text -
Click to expand...

Miro was that in vb 2003 or vb 2005. I think the code above only apply
to vb 2005, have you ever done anything in vb 2003. I know i have read
in a couple of places that serial COM is very weak in 2003. Please
confirm that the code above is for 2003 or 2005
 
M

Miro

It was for 2005.

But out of the express :) so if you need to write a quick dummy app... you might be
ok downloading vb.net 2005 express.

I have never played with 2003.
Ive been playing with 2005 left and right trying to slowly learn it.

M.
I have played with the serial port but What I used was by the event.
I did not use a timer.

I dont know if this is relevant for you or not?

Private Sub ListeningSerialPort_DataReceived(ByVal sender As System.Object, ByVal e As
System.IO.Ports.SerialDataReceivedEventArgs) Handles ListeningSerialPort.DataReceived

Dim ReceivingText As String = ""
ReceivingText = ListeningSerialPort.ReadLine

I played with this to hook a barcode scanner and throw the readings into a text box.

Miro


This code below write a serial command to the com port then read the
results and disaplays it into the label1.text property when
button1_click event is triggered. I think what is going on is that the
ocp.read is on a timer and reads char by char. How can i change this
code so that the read reads the whole result and not char by char?
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Me.Label1.Text = String.Empty
Try
' Enable the timer.
' Write an user specified Command to the Port.
oCP.Write("[REQ]")
WriteMessage("") ', True)
Catch ex As Exception
' Warn the user.
MessageBox.Show("Unable to write to comm port")
Finally
'TextBox1.Text = ""
'TextBox1.Focus()
End Try
End Sub
Private Sub tmrRead_Tick(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles tmrRead.Tick
Try
' As long as there is information, read one byte at a time
and
' output it.
While (oCP.Read(1) <> -1)
' Write the output to the screen.
WriteMessage(Chr(oCP.InputStream(0))) ', False)
End While
Catch exc As Exception
' An exception is raised when there is no information to
read.
' Don't do anything here, just let the exception go.
End Try
End Sub
' This subroutine writes a message to the txtStatus TextBox.
Private Sub WriteMessage(ByVal message As String)
' Me.TextBox2.Text += message + vbCrLf
Me.Label1.Text += message
' TextBox2.SelectionStart = TextBox2.Text.Length
End Sub
' This function returns an integer specifying the number of bytes
' read from the Comm Port. It accepts a parameter specifying the
number
' of desired bytes to read.
Public Function Read(ByVal Bytes2Read As Integer) As Integer
Dim iReadChars, iRc As Integer
' If Bytes2Read not specified uses Buffersize
If Bytes2Read = 0 Then Bytes2Read = miBufferSize
If mhRS = -1 Then
Throw New ApplicationException( _
"Please initialize and open port before using this
method")
Else
' Get bytes from port
Try
' Purge buffers
'PurgeComm(mhRS, PURGE_RXCLEAR Or PURGE_TXCLEAR)
' Creates an event for overlapped operations
If meMode = Mode.Overlapped Then
pHandleOverlappedRead(Bytes2Read)
Else
' Non overlapped mode
ReDim mabtRxBuf(Bytes2Read - 1)
iRc = ReadFile(mhRS, mabtRxBuf, Bytes2Read,
iReadChars, Nothing)
If iRc = 0 Then
' Read Error
Throw New ApplicationException( _
"ReadFile error " & iRc.ToString)
Else
' Handles timeout or returns input chars
If iReadChars < Bytes2Read Then
Throw New IOTimeoutException("Timeout
error")
Else
mbWaitOnRead = True
Return (iReadChars)
End If
End If
End If
Catch Ex As Exception
' Others generic erroes
Throw New ApplicationException("Read Error: " &
Ex.Message, Ex)
End Try
End If
End Function- Hide quoted text -
Click to expand...
- Show quoted text -
Click to expand...

Miro was that in vb 2003 or vb 2005. I think the code above only apply
to vb 2005, have you ever done anything in vb 2003. I know i have read
in a couple of places that serial COM is very weak in 2003. Please
confirm that the code above is for 2003 or 2005
Click to expand...
 
D

Dick Grier

Hi,

I suggest that you go to my homepage and download DesktopSerialIO (free).
This makes reading the serial port much easier. You can use a Timer, or
OnComm receive event processing. Normal code (including the terminal
example included) reads ALL available data each time you call InputString
(text data) or InputArray (binary data).

Dick

--
Richard Grier, MVP
Hard & Software
Author of Visual Basic Programmer's Guide to Serial Communications, Fourth
Edition,
ISBN 1-890422-28-2 (391 pages, includes CD-ROM). July 2004, Revised March
2006.
See www.hardandsoftware.net for details and contact information.
 

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