Serial Port Switcher using VB6...

[_Lurker_]

^^ Tama ba ang title?

Anyway I just want to share this simple vb6 serial port switcher. I test this using a usb-to-serial cable.
I have never tried this on the built-in serial port of a PC. The difference between the two is that
the cable has low -> 0 volts and high -> 5 volts. While the PC's serial port has a low of -9volts and
a high of +9volts, this depends on the PC used.

I don't know if this simple VB6 program may help anyone. But I think this is the simplest way
to interface a circuit to a PC. I might be wrong.



Three buttons could be connected to DTS, CD and CTS. If a high signal is detected, a "true" is displayed
on the appropriate text box. VB.net could sense the RING terminal, but as of now I don't know how to do that
in VB6. It might also be possible to make the RX terminal an input. What I know is the TX pin could be used as an output.

Code:

Private Sub cmdDTR_Click()
If cmdDTR.Caption = "ON" Then
cmdDTR.Caption = "OFF"
MSComm1.DTREnable = True
Exit Sub
End If

If cmdDTR.Caption = "OFF" Then
cmdDTR.Caption = "ON"
MSComm1.DTREnable = False
Exit Sub
End If
End Sub

Private Sub cmdRTS_Click()
If cmdRTS.Caption = "ON" Then
cmdRTS.Caption = "OFF"
MSComm1.RTSEnable = True
Exit Sub
End If

If cmdRTS.Caption = "OFF" Then
cmdRTS.Caption = "ON"
MSComm1.RTSEnable = False
Exit Sub
End If
End Sub

Private Sub cmdExit_Click()
If MSComm1.PortOpen Then MSComm1.PortOpen = False   'makes sure that the com port is close during exit
End
End Sub

Private Sub cmdConnect_Click()
On Error GoTo errorhandler

If MSComm1.PortOpen = True Then
MSComm1.PortOpen = False
cmdConnect.Caption = "CONNECT"
Label1.Enabled = True
Text1.Enabled = True
Text2 = ""
Text3 = ""
Text4 = ""
cmdDTR.Enabled = False
cmdRTS.Enabled = False
Exit Sub
End If

If MSComm1.PortOpen = False Then
MSComm1.CommPort = Text1.Text
MSComm1.PortOpen = True
cmdConnect.Caption = "DISCONNECT"
Text1.Enabled = False
Label1.Enabled = False
Text2.Text = MSComm1.DSRHolding
Text3.Text = MSComm1.CDHolding
Text4.Text = MSComm1.CTSHolding
cmdDTR.Enabled = True
cmdRTS.Enabled = True
End If
Exit Sub

errorhandler:
MsgBox "Wrong ComPort number"    ' for now i dont know any other errors
End Sub

Private Sub Form_Load()
With MSComm1
.DTREnable = False
.RTSEnable = False
End With
End Sub

Private Sub MSComm1_OnComm()
Text2.Text = MSComm1.DSRHolding
Text3.Text = MSComm1.CDHolding
Text4.Text = MSComm1.CTSHolding
End Sub

Private Sub Timer1_Timer()
If Form1.Caption = "SERIAL PORT SWITCHER" Then
Form1.Caption = "WWW.ELECRONICSLAB.PH"
Exit Sub
End If
If Form1.Caption = "WWW.ELECRONICSLAB.PH" Then
Form1.Caption = "SERIAL PORT SWITCHER"
Exit Sub
End If
End Sub

A proper series resistor should be used on each terminal.

[_Lurker_]

http://www.easy-share.com/1917978134/serial port switcher.zip

[PlCUSER]

nice post. +1 for sharing.

in addition, you can use the mscomm event "comEvRing" to monitor RI pin. a change status in this pin triggers this event.
below are other mscomm events in VB6:
comEvCD
comEvCTS
comEvDSR
comEvRing
             

baka pwd mo ding ishare ung hardware set up mo. para complete package na ang post.
and mas maka relate ung mga mapapadaan.

[_Lurker_]

^^^ Maraming salamat sir sa point at sa payo. "comEvRing" lang pala ang katapat. +1
OK sir gagawa po ako ng schem.. Bagong reformat kasi PC ko, mag iinstall pa ako ng proteus at vb6.

[_Lurker_]

Ito na po simple hardware. Yung 5 volts doon na kunin sa 5 volts supply sa USB-to-Serial, baklasin nalang yung wire.

[ultrasonic™]

nice  sharing sis  dummy... hiramin  ko na rin  ito 

[Supremo Mayor Kuya Johnaray]

+ 1 Nice Thanks for sharing... MOAR MOAR este MORE!

[_Lurker_]

^^^ Salamat din po.

Nahirapan pa ako magamit ang Ring terminal sir PICUSER. Na detect ko na ang comEvRing pero mahirap ipa labas sa text box ang pag open/close ng switch. Isang beses lang kasi sya mag trigger. At pag na disconnect na yung switch, wala ng commevent. 

[PlCUSER]

meron kasi atang hindi tama sa set up mo sir. hehehe.
the proper way to trigger an event on these pins is to pull these pins low. connect mo sa ground ung switch, not sa +5V. in doing so, pwd mo na din alisin ung 1k resistor.

but for good pc interfacing practice, always use an optocoupler. like the PC817.

[_Lurker_]

Na dagdagan ng isang output..

[IMG=http://img192.imageshack.us/img192/9431/hardware2.jpg][/IMG]

Uploaded with ImageShack.us

http://www.easy-share.com/1917998828/serial port switcher.zip

[Hotguy]

Pasub..   Thanks sir pulang kabayo sa pagshare...Dadagdagan ko pa ng 1 point if madagdagan pa ng info

[_Lurker_]

meron kasi atang hindi tama sa set up mo sir. hehehe.
the proper way to trigger an event on these pins is to pull these pins low. connect mo sa ground ung switch, not sa +5V. in doing so, pwd mo na din alisin ung 1k resistor.

but for good pc interfacing practice, always use an optocoupler. like the PC817.

OK sir try ko modify yung circuit.. Maraming salamat po. Teka bakit hindi lalabas ang image sa taas?

[_Lurker_]

Repost ko lang po..




http://www.easy-share.com/1917998828/serial_port_switcher.zip

[Hotguy]

nyc.. i like that

[Phthonos]

super thnx po tlga master dummy_c! sna po mgwa nio ung 4 switches if possible
pero thnx po tlga d2 O:D

[Lhean]

panu po kung ang need ko 4 switch...

[Lhean]

panu po kung 4 switch ang need kong ikabit...

[Kaizer03]

gamitan mo ng diodes to multiplex those three inputs.. para maging 7 inputs

001
010
100
011
110
101
111

same thing with output=)

[_Lurker_]

^^^ Sir kaizer salamat po. But what if dalawa or tatlo na switch sabay sabayin na i-pendot sir? Pwede pa rin kaya? Salamat po.

[Kaizer03]

^

kung gagamitin mo lahat ng combination.. malamang di na kasi may dodoble... pero kung 4 lang gagamitin mo..make it sure na walang kaparehas na combination yung pedeng magkasabay na button =)