Visual Basic

king_of_inismac

Ok guys, heres my problem

Have a microcontroller connected to my PC. I'm communicating with the controller using VB and the mscomm control.

I can send commands to the controller, and they work fine.
The problem is dealing with data sent from the controller to the PC. I want to be able to see the responses.



When data is received a com event is triggered.

There is a byte of data on the input buffer.

When I use mscomm1.input to retrieve the data, it returns a string. This is really a byte to information that I need to do some processing on....

How do I convert from the string format to a byte format where the result is in the form:

00100010

I've tried using the Cbyte function, but it says type mismatch.

Also would anyone know how to extract the upper and lower nibble from the byte. I'd imagine you would use the mid$ function?

Cheers in advance,

Martin

Hobbes

If you have bit shifting in VB (I forget) you just shuffle your bits across by 4.

charlo_b

Does this help??? Could probably be modified to suit your needs

Private Sub Form_Load()
Dim sCharstring As String
Dim colBytes As Collection

    sCharstring = "and"
    Set colBytes = CharStringToBitStringCol(sCharstring)
    
    MsgBox "The word is :" & sCharstring & vbCrLf & _
           "-------------------------------------" & vbCrLf & _
           Mid(sCharstring, 1, 1) & " = " & colBytes(1) & " : Upper Nibble = " & Mid(colBytes(1), 1, 1) & " : Lower Nibble = " & Mid(colBytes(1), 8, 1) & vbCrLf & _
           Mid(sCharstring, 2, 1) & " = " & colBytes(2) & " : Upper Nibble = " & Mid(colBytes(2), 1, 1) & " : Lower Nibble = " & Mid(colBytes(2), 8, 1) & vbCrLf & _
           Mid(sCharstring, 3, 1) & " = " & colBytes(3) & " : Upper Nibble = " & Mid(colBytes(3), 1, 1) & " : Lower Nibble = " & Mid(colBytes(3), 8, 1)
    
End Sub

Private Function CharStringToBitStringCol(ByVal sChar As String) As Collection
Dim bByte() As Byte

    Set CharStringToBitStringCol = New Collection
    ReDim bByte(Len(sChar))
    
    For i = 1 To Len(sChar)
        bByte(i - 1) = CByte(Asc(Mid(sChar, i, 1)))
        CharStringToBitStringCol.Add (bByte(i - 1) And 128) / 128 & _
                                    (bByte(i - 1) And 64) / 64 & _
                                    (bByte(i - 1) And 32) / 32 & _
                                    (bByte(i - 1) And 16) / 16 & _
                                    (bByte(i - 1) And 8) / 8 & _
                                    (bByte(i - 1) And 4) / 4 & _
                                    (bByte(i - 1) And 2) / 2 & _
                                    (bByte(i - 1) And 1) / 1
                                    
    Next
    
    
    
End Function

king_of_inismac

Thanks for the help so far guys

well, Ive been working on the code myself, and I've got this much working:

count = MSComm1.InBufferCount

sData = MSComm1.Input

Debg.Text = "In buffer: " & count
TotalByte = sData

arrLen = UBound(TotalByte)

buffer.Text = "Array length: " & arrLen + 1

For i% = 0 To (1) Step 1
Int_byte(i%) = CInt(TotalByte(i%))
Hex_byte(i%) = Hex(Int_byte(i%))
Next i%

receivedData.Text = Hex_byte(0) & Hex_byte(1)


This piece of code converts mscomm1.input from string to decimal and from decimal to hex as required.

It works fine with 1 byte returned. However, the response from 1 particular command is 4 bytes long, and something weird happens. The input buffer length is 4 as expected, but the totalByte byte array size is only 2....

What happened to the other bytes?

TotalByte is declared as Dim TotalByte() As Byte

Dunno why this is happening?

Capt'n Midnight

Does it return a single character A$ ?

[php]
v=asc(a$)
Lnibble =v and 15
Lnibble =v mod 16

Hnibble = v \ 16
Hnibble = (v and 240 ) /16
[/php]

If it returns a 8 character string then there should be a built in function to return it value, though you may need to add formating characters to it to indicate it's a Binary represtentatin..