Serial Port Configuration Dialog

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Introduction

Quite a few times in my hardware projects, I had to send some calibration data between a microcontroller (Microchip PIC) and a PC through a serial port (RS-232). The software on the PC side is written in VB6 with an MSComm control. The latter has to be configured with parameters: port number, baud rate, number of data bits, number of stop bits. Configuration of an MSComm is a fairly common task (it used to be even more common in the past). So, at first I thought that there should be a dialog for that available on the web. Unfortunately, such a dialog was nowhere to be found, and I wrote one myself. Hopefully, it turned out generic and reusable enough.

Features

• Automatic detection of serial ports
• The most recent port settings are stored in the INI file
• Interface supports configuration of multiple ports in the same program

Dialog

Configuration is done in the frmComm dialog.

ShowConfig

Declaration

Public Function ShowConfig( _ 
    ByRef comm As MSComm, _ 
    Optional ByRef strIniFile As String, _ 
    Optional ByRef strSection As String) _ 
    As VbMsgBoxResult 

Purpose

Set-up the configuration dialog and show it to the user. cboPort is copulated with a list of available COM ports.

Parameters

• ByRef comm As MSComm

  MSComm which will be configured in the dialog. If the comm is already open, the GUI is pre-loaded with its configuration and is comm closed.

• Optional ByRef strIniFile As String

  Optional name of the INI file containing configuration information. GUI is pre-loaded with the settings from the INI file.

• Optional ByRef strSection As String

  Optional name of the section in the INI file containing the configuration information. If the section name is not supplied, default name serial_port is used.

Return Value

• vbOK when configuration was successful
• vbCancel when user decided to cancel configuration

QuietConfig

Declaration

Public Function QuietConfig( _ 
    ByRef comm As MSComm, _ 
    ByRef strIniFile As String, _ 
    ByRef strSection As String) _ 
    As VbMsgBoxResult 

Purpose

Configure the target MSComm with parameters from the local file without showing the configuration dialog.

Pre-conditions

The supplied INI file contains the configuration information.

Post-conditions

The target MSComm is configured but not opened.

Parameters

• ByRef comm As MSComm

  MSComm will be configured from the INI file. If the comm is already open, it will be closed.

• ByRef strIniFile As String

  Optional name of the INI file containing configuration information. GUI is pre-loaded with the settings from the INI file.

• ByRef strSection As String

  Optional name of the section in the INI file containing the configuration information. If the section name is not supplied, default name serial_port is used.

Return Value

• vbOK when configuration was successful
• vbAbort if the INI file was erroneous or non-existent

INI file

Loading and Saving

The dialog is populated with the parameters from the INI file, if the name of the file is supplied.

Structure

Multiple sections for multiple ports within the same INI file, or individual INI files for multiple ports. The name of the INI file section can be chosen by the user, the default name is serial_port.

KEY: CommPort - port number as in MSComm.CommPort

KEY: Settings - port settings same format as in MSComm.Settings

Closing Remarks

Please let me know if you find any bugs or have any suggestions!

References

[1] Serial port configuration dialog in HyperTerminal

[2] Root MSDN article for MSComm control
http://msdn2.microsoft.com/en-us/library/aa259393.aspx

Revision History