Const GENERIC_READ          = $80000000
Const GENERIC_WRITE         = $40000000
Const OPEN_EXISTING         = 3
Const FILE_ATTRIBUTE_NORMAL = $80
Const INVALID_HANDLE_VALUE  = -1
Const NOPARITY              = 0
Const ONESTOPBIT            = 0

Function OpenCommPort%(Port%)
   Local File%

   If (Port < 0) Or (Port > 255) Then Return -1
   
   ; Open CommPort
   File% = apiCreateFile("COM"+Port%, GENERIC_READ Or GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0)
   If File% = INVALID_HANDLE_VALUE Then
      Return -1
   Else
      Return File%
   EndIf
End Function

Function CloseCommPort%(File%)
   Return apiCloseHandle(File%)
End Function

Function SetCommBaudrate%(File%, Baudrate%)
   Local DCB%
   
   DCB% = CreateBank(28)
   
   ; Get States
   If apiGetCommState(File%, DCB) = 0 Then
      FreeBank DCB%
      Return False
   ElseIf PeekInt(DCB%, 0) <> 28
      FreeBank DCB%
      Return False
   EndIf

   PokeInt  DCB%,  4, Baudrate   ; Baudrate
   PokeByte DCB%, 18, 8          ; Byte Size
   PokeByte DCB%, 19, NOPARITY   ; Parity
   PokeByte DCB%, 20, ONESTOPBIT ; StopBits
   
   ; Set States
   If apiSetCommState(File%, DCB%) = 0 Then
      FreeBank DCB%
      Return False
   Else
      FreeBank DCB%
      Return True
   EndIf
End Function

Function SetCommTimeouts%(File%, ReadTime%, WriteTime%)
   Local TimeOuts%
   
   ; Get timeouts
   Timeouts% = CreateBank(40)
   If apiGetCommTimeouts(File%, Timeouts%) = 0 Then
      FreeBank Timeouts
      Return False
   EndIf
   
   PokeInt Timeouts%,  8, ReadTime%  ; ReadTotalTimeoutConstant
   PokeInt Timeouts%, 16, WriteTime% ; WriteTotalTimeoutConstant
   
   ; Set Timeouts
   If apiSetCommTimeouts(File%, Timeouts%) = 0 Then
      FreeBank Timeouts
      Return False
   Else
      FreeBank Timeouts
      Return True
   EndIf
End Function

File% = OpenCommPort(1)

Print File%
Print SetCommBaudrate(File%, 9600)
Print SetCommTimeouts(File%, 1000, 1000)
Print CloseCommPort(File%)
Print CloseCommPort(File%)

WaitKey
End

Function WriteComm%(File%, Buffer%, Size%)
   Local Count%, Count2%

   If Size% > BankSize(Buffer%) Then Return 0
   
   Count% = CreateBank(4)
   
   If apiWriteFile(File%, Buffer%, Size%, Count%, 0) = 0 Then
      FreeBank Count%
      Return 0
   Else
      Count2% = PeekInt(Count%, 0)
      FreeBank Count%
      Return Count2%
   EndIf
End Function

Function ReadComm%(File%, Buffer%, Size%)
   Local Count%, Count2%
   
   If Size% > BankSize(Buffer%) Then Return 0
   
   Count% = CreateBank(4)
   
   If apiReadFile(File%, Buffer%, Size%, Count%, 0) = 0 Then
      FreeBank Count%
      Return 0
   Else
      Count2% = PeekInt(Count%, 0)
      FreeBank Count%
      Return Count2%
   EndIf
End Function