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I am running Windows XP pro SP2.
The device is a QBridge-I2C-USB host adaptor . It uses an 8-bit PIC 18F2455 chip,
(I posted on microchip site too but no reply yet).
I downloaded some sample code from http://www.qprotos.com/downloads.htm, I got the QBridge-I2C-USB V1.41 installation files (application, driver, samples), from the website...
It gives 2 versions for the samples. One uses mpusbapi.dll, and the other one uses mpusbapi_vb.dll. I've tried both and the one that uses mpusbapi_vb.dll looks closer to what I need, so I will talk about that one.
jtr_USB_Vb6_Original_code.txt (24.79K)
Number of downloads: 493
I hooked up the hardware including the QBridge-I2C-USB and the I2C device (a Taos TCS3414 light sensor),
and tested it using the downloaded program.
Everything worked fine, and I was able to manually write and read from the light sensor and get light readings from it with no problem.
Ok great... now I just have to write my own application to do all the stuff I want......
I can just start with the sample code and edit it from there, right ???
I attached all the original and updated code for reference, I will detail smaller chunks below,
(I tried to put everything in here before , butthe post got cut off at the bottom)
Well it turns out it is not quite that easy.....
The code is written in VB6, which I don't have. (I did find some old Visual Studio 5 discs that msdn sent to me years ago, but I figured that they were probably too old...)
So I went to the msdn site and downloaded VBexpress2008 and installed it, and when I went to open the project file, It insisted on UPGRADING the code to VB2008.....................
Ok.....So Iet VB2008 do its Upgrade thing, And this is what I got:
jtr_USB__VB2008_upgraded_code.txt (24.33K)
Number of downloads: 552
When I tried to build it, I got these warnings and errors:
--------------------------------------------------------------------------------------------
(msg), File, Line, Description
(Warning), VB6_QBrige_frm.vb, 30, function 'CalXOrChksum'does't return a value on all code paths. A null reference exception could occur at run time when the result is used.
(Error), VB6_QBrige_bas.vb, 129, Name 'VarPtr' is not declared.
(Error), VB6_QBrige_bas.vb, 132, Name 'VarPtr' is not declared.
--------------------------------------------------------------------------------------------
so I went to look at the errors first, and found this error:
'UPGRADE_ISSUE: VarPtr function is not supported.
(This is the snippet with the VarPtr error, all the orginal and upgraded code is attached also)
'/////////////-< Code With VarPtr Errors >-BEGINNING//////////////////////// '///////////////////////////////////////////////////////////////////////////// '// '// A typical application would send a command to the target device and expect '// a response. '// SendReceivePacket is a wrapper function that facilitates the '// send command / read response paradigm '// '// SendData - pointer to data to be sent '// SendLength - length of data to be sent '// ReceiveData - Points to the buffer that receives the data read from the call '// ReceiveLength - Points to the number of bytes read '// SendDelay - time-out value for MPUSBWrite operation in milliseconds '// ReceiveDelay - time-out value for MPUSBRead operation in milliseconds '// Function SendReceivePacket(ByRef SendData() As Byte, ByRef SendLength As Integer, ByRef ReceiveData() As Byte, ByRef ReceiveLength As Integer, ByVal SendDelay As Integer, ByVal ReceiveDelay As Integer) As Integer Dim SentDataLength As Integer Dim ExpectedReceiveLength As Integer ExpectedReceiveLength = ReceiveLength If (myOutPipe <> INVALID_HANDLE_VALUE And myInPipe <> INVALID_HANDLE_VALUE) Then 'UPGRADE_ISSUE: VarPtr function is not supported. Click for more: 'ms-help://MS.VSCC.v90/dv_commoner/local/redirect.htm?keyword="367764E5-F3F8-4E43-AC3E-7FE0B5E074E2"' If (MPUSBWrite(myOutPipe, VarPtr(SendData(0)), SendLength, SentDataLength, SendDelay) = MPUSB_SUCCESS) Then 'UPGRADE_ISSUE: VarPtr function is not supported. Click for more: 'ms-help://MS.VSCC.v90/dv_commoner/local/redirect.htm?keyword="367764E5-F3F8-4E43-AC3E-7FE0B5E074E2"' If (MPUSBRead(myInPipe, VarPtr(ReceiveData(0)), ExpectedReceiveLength, ReceiveLength, ReceiveDelay) = MPUSB_SUCCESS) Then If (ReceiveLength <= ExpectedReceiveLength) Then SendReceivePacket = 1 '// Success! Exit Function End If Else CheckInvalidHandle() End If Else CheckInvalidHandle() End If End If SendReceivePacket = 0 '// Operation Failed End Function '/////////////////////-< Code With VarPtr Errors >-END////////////////////////
I googled around to find stuff on pointers, And it looks like for pointer stuff, you are supposed to use "marshaling" for VB2008. ( Thats a new one for me..... makes me think of guys from microsoft with sheriff's badges )
So I dug around some more and I found this VarPtr replacement code on PlanetSourceCode:
< VarPtr replacement from PlanetSourceCode >
'/////////-< VarPtr replacement from PlanetSourceCode>-BEGINNING///////// Public Function VarPtr(ByVal o As Object) As Integer Dim GC As System.Runtime.InteropServices.GCHandle = _ System.Runtime.InteropServices.GCHandle.Alloc(o, System.Runtime.InteropServices.GCHandleType.Pinned) Dim ret As Integer = GC.AddrOfPinnedObject.ToInt32 GC.Free() Return ret End Function '//////////-< VarPtr replacement from PlanetSourceCode>-END//////////
I stuck in the VarPtr replacementCode before the Sub CheckInvalidHandle().
I can build it ok now, but I still get this warning:
--------------------------------------------------------------------------------------------
(msg), File, Line , Description
(warning), VB6_QBrige_frm.vb, 30, function 'CalXOrChksum'does't return a value on all code paths. a null reference exception could occurat run time when the result is used.
--------------------------------------------------------------------------------------------
(Ill put the Snippet with this error in the next post because I dont have enough room here.)
I copied mpusbapi_vb.dll into the Bin folder.
I Started Debug, and when I clicked :
Open USB button, I get: Msgbox(Windows Error 31),
When I click ok, I get: Failed To openI2C Port,
When I click ok, I get: Msgbox(Windows Error 997)
When I click ok, I get: Msgbox(Failed to set BaudRate)
-----------------------------------------------
I wrote some test code to check the pipes, and when I called OpenMPUSBDevice() I could see the handles:
myOutPipe = 1308
myInPipe = 1356
When I called CloseMPUSBDevice() I could see:
myOutPipe = -1
myInPipe = -1
and I could repeat opening and closing a few times ok.
When I unplug the USB and try it again, the msg box pops up and says "No Devices Connected",
so that seems to look ok ........
Now I must confess that this is the first time in my life that I have ever tried to make a USB device interface with anything.......
(The last time I played with VB was so long ago that I don't think USB had even been invented yet...)
Does anybody have any idea about:
1) How can I cure the the CalXOrChksum warning?
2) Is that VarPtr replacement snippet ok?
3) Am I missing something, or doing something really dumb?
4) Should I be using a different approach to the USB interface for VB2008?
Any help or advice would be much appreciated.....
Thx
jtr
This post has been edited by jtr: 26 January 2009 - 05:48 PM
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