Hi,

Has anyone got a sample code of how to Open/Close/Read/Write from COM Port with these functions:

CreateFile,ReadFile,WriteFile,GetCommProperties,GetLastError,GetCommState,SetCommState

or using MSCOMM.OCX

which one is easier to use?

Thanks

Ana,

I have done some work on mmcomm and have it working - created something like a HyperTerminal form to provide a test bed. The trick of serial comm is that you need to 'listen' to the comm buffer and take out whats there and re-assemble into useable chunks of data. Contact me for more info.

One of my next projects to change to the Win API which should be much more robust than an a pretty dated ocx. I know Revelation was looking at typing the Win API - you might like to check with Mike as to progress.

Richard Bright

r.bright@ark.co.nz

For what its worth, we have some code, but its work in progress at the moment. Works fine for 16bit, but with 32 bit we had to change it all as Microsoft use different methods.

Code is below, but user beware…

You will of course need to declare the functions for the DLLs, we have applied our own extensions to avoid risk of Revelation clashes.

Having said all that there are issues at the moment (ie it doesnt work) which we have not resolved, and we may need to use a different approach.

In the meantime, I use a VB program to do the comms, and then pass this to OpenInsight, there is a slight delay but its livable.

If you can make it work, wonderful, if not, Richards suggestions may be a better alternative, and I am just posting on the off chance it might help.

You will need to adjust the code to suit, my common and variables for passing etc.

Colin

---

COMPILE SUBROUTINE COMM_ACCESS(MODE,COMM_PORT_HANDLE,COMMDATA)

* STANDARD

* Open/Close Comm port, Read/Write to port

* AG - May 96

*

$INSERT ICEPAC_COMMON

DECLARE FUNCTION BLANK_STRUCT,GET_PROPERTY,STRUCT_TO_VAR,VAR_TO_STRUCT

DECLARE FUNCTION OpenComm,CloseComm,BuildCommDCB,SetCommState,ReadComm,WriteComm

DECLARE FUNCTION CreateFileCSSP32,CloseCommCSSP32,BuildCommDCBCSSP32,SetCommStateCSSP32,ReadFileCSSP32,WriteFileCSSP32

DECLARE FUNCTION GetLastError,GetLastErrorCSSP32

BEGIN CASE

	CASE MODE=OPEN"	;GOSUB OPEN_PORT

	CASE MODE=CLOSE"	;GOSUB CLOSE_PORT

	CASE MODE=READ"	;GOSUB READ_FROM_PORT

	CASE MODE=WRITE"	;GOSUB WRITE_TO_PORT

END CASE

RETURN

OPEN_PORT:

COMM_ERRORS="

COMM_ERRORS=-1 ;COMM_ERRORS=Invalid or unsupported device"

COMM_ERRORS=-2 ;COMM_ERRORS=Device already in use"

COMM_ERRORS=-10;COMM_ERRORS=Device already in use"

COMM_ERRORS=-12;COMM_ERRORS=Device baud rate is invalid"

PORT	 =COMMDATA

BAUD_RATE=COMMDATA

DATA_BITS=COMMDATA

STOP_BITS=COMMDATA

PARITY	 =COMMDATA1,1

FLOW_CONTROL=COMMDATA1,1

PORT_SETTINGS=PORT:":":BAUD_RATE:",":PARITY:",":DATA_BITS:",":STOP_BITS:\00\

INQSIZE=1024

OUTQSIZE=128

IF BITSIZE=16 THEN

	PORT=PORT:\00\

	COMM_PORT_HANDLE=OpenComm(PORT,INQSIZE,OUTQSIZE)

END ELSE

	ShareMode=1

	CreationDisposition=3

	COMM_PORT_HANDLE=CreateFileCSSP32(PORT,"",ShareMode,"",CreationDisposition,"","")

END

LOCATE COMM_PORT_HANDLE IN COMM_ERRORS USING @VM SETTING POS THEN

	COMM_PORT_HANDLE=COMM_ERRORS

	RETURN

END

DCBCode=DCB"

DCB_STRUCT=BLANK_STRUCT(DCBCode)

IF BITSIZE=16 THEN

	RETVAL=BuildCommDCB(PORT_SETTINGS,DCB_STRUCT)

END ELSE

	RETVAL=BuildCommDCBCSSP32(PORT_SETTINGS,DCB_STRUCT)

END

COMM_PARAMS=STRUCT_TO_VAR(DCB_STRUCT,DCBCode)

BEGIN CASE

	CASE FLOW_CONTROL=X"

		COMM_PARAMS=3

	CASE FLOW_CONTROL=H"

		COMM_PARAMS=5

		COMM_PARAMS=9

		COMM_PARAMS=64

END CASE

DCB_STRUCT=VAR_TO_STRUCT(COMM_PARAMS,DCBCode)

IF BITSIZE=16 THEN

	RETVAL=SetCommState(DCB_STRUCT)

END ELSE

	RETVAL=SetCommStateCSSP32(DCB_STRUCT)

END

RETURN

CLOSE_PORT:

IF BITSIZE=16 THEN

	RETVAL=CloseComm(COMM_PORT_HANDLE)

END ELSE

	RETVAL=CloseCommCSSP32(COMM_PORT_HANDLE)

END

RETURN

READ_FROM_PORT:

IF BITSIZE=16 THEN

	BUFF_LEN=50

	COMMDATA=STR(\00\,BUFF_LEN)

	RETVAL=ReadComm(COMM_PORT_HANDLE,COMMDATA,BUFF_LEN)

	COMMDATA=FIELD(COMMDATA,\00\,1)

END ELSE

	BytesToRead=1024

	BytesRead=0

	BUFF_LEN=50

	COMMDATA=50

	RETVAL=ReadFileCSSP32(COMM_PORT_HANDLE,COMMDATA,BytesToRead,BytesRead,"")

	ERROR="

	RETVAL2=GetLastErrorCSSP32(ERROR)

END

RETURN

WRITE_TO_PORT:

COMMDATA=COMMDATA:\00\

BUFF_LEN=LEN(COMMDATA)

IF BITSIZE=16 THEN

	RETVAL=WriteComm(COMM_PORT_HANDLE,COMMDATA,BUFF_LEN)

END ELSE

	RETVAL=WriteFileCSSP32(COMM_PORT_HANDLE,COMMDATA,BUFF_LEN)

END

RETURN

Thank for your help with the code, but How can i get your program in VB , at this moment is a great option.

I need to comunicate with a MS2200 series StratosS™

This is the link :

http://www.metrologic.com/corporate/products/pos/MS2200.htm

Can you give some options , what can You do for me?

Thanks

I presume you intend to use the RS232 interfaces.

You no doubt have a cable for this, we used to solder them up ourselves in the old days.

Below is my VB program, there is stuff in it which wont be relevant, and I use to pass info back and forwards, log files and the like.

I have a small VB form with a timer control and the MSComm control on it, as well as a edit box to advise whats going on, but this EXE is run as a background program normally.

It will need to have many changes to work with this scanner, as there may be a whole range of things it needs. It probably has the ability to send and receive information, but you need to know the procotols for these.

If you give me your Email address I can send some screen shots and examples.

Good luck

Colin

—– VB CODE FOLLOWS ———

Option Explicit

Dim sPath   As String

Dim sCommand As String

Dim sArgs()  As String

Dim InBuff As String

Dim sText As String

Dim LastBuff As String

Dim SoundFile As String

Private Declare Function sndPlaySound Lib "winmm.dll" Alias "sndPlaySoundA" (ByVal Filename As String, ByVal Flags As Long) As Long

   Private Sub Form_Load()

       sCommand=Command & ",,,,,,,"

       If sCommand=" Then

           sCommand=Comm1,9600,N,8,1,C:\,"

          'sCommand=Comm2,9600,N,8,1,C:\,"

       End If

       sArgs()=Split(sCommand, ",")

       sPath=sArgs(5)

       SoundFile=sArgs(6)

       Text.Text="

       LastBuff="

       If sPath=" Then sPath=C:\"

       If Dir(sPath & "digit.log")  "" Then

          Kill sPath & "digit.log"

       End If

       Open sPath & "digit.log" For Append As #99

       WriteToLog "Command line=" & sCommand & "'"

       WriteToLog "Path=" & sPath & "'"

       WriteToLog "Comm port=" & Right(sArgs(0), 1) & "'"

       WriteToLog "Comm port settings=" & sArgs(1) & "," & sArgs(2) & "," & sArgs(3) & "," & sArgs(4) & "'"

       WriteToLog "Sound File=" & SoundFile & "'"

       With MSComm1

          .CommPort=Right(sArgs(0), 1)

          .Handshaking=2 - comRTS

          .RThreshold=1

          .RTSEnable=True

          .Settings=sArgs(1) & "," & sArgs(2) & "," & sArgs(3) & "," & sArgs(4)

          .SThreshold=1

          .PortOpen=True

          .InBufferCount=0

          .InputLen=1

       End With

       WriteToLog "Comm port opened"

       WriteToLog "RTS Enabled"

       WriteToLog "Comm port buffer cleared"

       WriteToLog "Ready to receive data..."

       InBuff="

    End Sub

  Private Sub Form_Unload(Cancel As Integer)

      If Dir(sPath & "dinfo.txt")  "" Then

          Kill sPath & "dinfo.txt"

      End If

      MSComm1.PortOpen=False

      WriteToLog "Comm port closed"

      WriteToLog "End of session"

      Close #99

  End Sub

   Private Sub MSComm1_OnComm()

      Dim InChar As String

      Dim Counter As Integer

      Select Case MSComm1.CommEvent

          Case comEventBreak     ' A Break was received.

              Unload (Form1)

          Case comEventCDTO      ' CD (RLSD) Timeout.

              Unload (Form1)

          Case comEventCTSTO     ' CTS Timeout.

              Unload (Form1)

          Case comEventDSRTO     ' DSR Timeout.

              Unload (Form1)

          Case comEventTxFull    ' Transmit buffer full.

              Unload (Form1)

          Case comEventFrame     ' Framing Error

          Case comEventOverrun   ' Data Lost.

          Case comEventRxOver    ' Receive buffer overflow.

          Case comEventRxParity  ' Parity Error.

          Case comEventDCB       ' Unexpected error retrieving DCB]

          Case comEvCD           ' Change in the CD line.

          Case comEvCTS          ' Change in the CTS line.

          Case comEvDSR          ' Change in the DSR line.

          Case comEvRing         ' Change in the Ring Indicator.

          Case comEvSend

          Case comEvEOF

          Case comEvReceive      ' Received RThreshold # of chars.

              InChar=MSComm1.Input

              If InChar=Chr$(10) Then InChar="

              If InChar=Chr$(13) Then

                  Open sPath & "digit.txt" For Append As #1

                  Print #99, "Data received: " & InBuff

                  Print #1, InBuff

                  Close #1

                  sText=Text.Text

                  Text.Text=sText & InBuff & Chr(13) & Chr(10)

                  LastBuff=InBuff

                  InBuff="

                  If SoundFile  "" Then

                      Call sndPlaySound(SoundFile, 1)

                  End If

              Else

                  InBuff=InBuff & InChar

              End If

       End Select

    End Sub

  Sub WriteToLog(sString As String)

      Print #99, Now & " - " & sString

      sText=Text.Text

      Text.Text=sText & sString & Chr(13) & Chr(10)

  End Sub

Private Sub Timer1_Timer()

  If Dir(sPath & "dinfo.txt")  "" Then Unload Me

End Sub

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