Byte Communication

[mbelew]

Im using the CreateFile and WritFile API call to send data to a serial device. The Code for my function containing the Create file call is:

Private Function OpenPort1(ByVal strPort As String, ByVal lngBaudRate As String, ByVal lngDataBit As Long) As Long
Dim pDCB As DCB
Dim lpPort As String

'// Create Comm Name Buffer
lpPort = "COM2" + strPort + vbNullChar


'// Close the current opened Comm Port (If any)
If hComm1 > 0 Then CloseHandle (hComm1)

'// Open selected comm port
hComm1 = CreateFile(lpPort, _
GENERIC_READ Or GENERIC_WRITE, _
0, _
ByVal 0, _
OPEN_EXISTING, _
FILE_FLAG_NO_BUFFERING, _
0)



If hComm1 <> INVALID_HANDLE_VALUE Then
pDCB.DCBlength = Len(pDCB)

'// Retrieve default Comm port settings
GetCommState hComm1, pDCB

'// Configure new Comm port settings
With pDCB
.BaudRate = lngBaudRate
.Parity = NOPARITY
.ByteSize = lngDataBit
.StopBits = 2
.EofChar = 0
.ErrorChar = 0
.EvtChar = 0
.fBitFields = 20625
.XoffChar = 0
.XoffLim = 0
.XonChar = 0
.XonLim = 0
End With

'// Set new configure Comm port settings
If SetCommState(hComm1, pDCB) = 0 Then
CloseHandle (hComm1)
OpenPort1 = 0

MsgBox "Fail to configure serial port COM11!", vbExclamation + vbOKOnly, "Error"
Else
OpenPort1 = hComm1
End If
Else
CloseHandle (hComm1)
OpenPort1 = 0
End If
End Function

and the function containing the WriteFile call is :
Private Sub Write1Port(ByVal strData As String)
Dim dwByteWrite As Long
Dim Sz As Long, Idx As Long
Dim Bytes() As Byte

'// Create & Convert str into array of Byte
Sz = Len(strData)
ReDim Bytes(Sz) As Byte
For Idx = 1 To Sz
Bytes(Idx - 1) = Asc(Mid$(strData, Idx, 1))
Next

'// Write data into Open Comm Port
If hComm1 <> INVALID_HANDLE_VALUE Then
WriteFile hComm1, _
Bytes(0), _
UBound(Bytes), _
dwByteWrite, _
ByVal 0&
Else
MsgBox "Cannot communicate through COM11", vbExclamation + vbOKOnly, "Error"
End If

Erase Bytes

End Sub

I only want to send one byte at a time to the device such as:

Write1Port &HC7

What changes can I make to send only the single byte to the serial device?