; kernel defined constants

Const OPEN_EXISTING        = 3
Const GENERIC_READ         = $80000000
Const GENERIC_WRITE        = $40000000
Const INVALID_HANDLE_VALUE = $FFFF
Const MAXDWORD             = $FFFF

; comms Constants

Const PURGE_TXCLEAR = $4
Const PURGE_RXCLEAR = $8

Const CE_RXOVER   = $1   ; Receive Queue overflow
Const CE_OVERRUN  = $2   ; Receive Overrun Error
Const CE_RXPARITY = $4   ; Receive Parity Error
Const CE_FRAME    = $8   ; Receive Framing error
Const CE_BREAK    = $10  ; Break Detected
Const CE_TXFULL   = $100 ; TX Queue is full

Const SETRTS = 3 ; Set RTS high
Const SETDTR = 5 ; Set DTR high


Function OpenComPort(strPortName$,strSettings$)
   Local tCto,tDcb,hPort,lErr
   tCto = CreateBank(20)
   tDcb = CreateBank(79)
   
   PokeInt tDcb,00,79 ; DCBLength
   
   ; get kernel To build a Default DCB For us
   ; based on com settings String
   BuildCommDCB(strSettings$,tCdb)
   
   ; open that com port
   hPort = CreateFile(strPortName$,GENERIC_READ + GENERIC_WRITE,0,0,OPEN_EXISTING,0,0)
   
   ; did we get port open ...
   If hPort = INVALID_HANDLE_VALUE Then
      lErr = GetLastError()
      DebugLog "Failed to open comport( err=" + Str$(lErr) + ")"
   
      ; setup return to failure
      Return INVALID_HANDLE_VALUE
   Else
      ; ... yes, get port ready for action
      SetCommState(hPort,tDcb)
      
      ; set up buffer sizes and re-initialize comm driver
      SetupComm(hPort,64000,64000)
      
      ; setup timeout parameters for this port
      PokeInt tCto,00,MAXDWORD
      PokeInt tCto,04,0
      PokeInt tCto,08,0
      PokeInt tCto,12,0
      PokeInt tCto,16,10000
      SetCommTimeouts(hPort,tCto)
      
      ; setup returns for success
      Return hPort
   EndIf
End Function

Function WriteCommPort(lPortHandle,strData$,cbData)
   Local fWrite,cbData,I,cdWritten,lErr,tComStat,lErrFLags
   
   cdData = CreateBank(Len(strData$)+1)
   For I = 1 To Len(strData$)
      PokeByte cdData,I-1,Asc(Mid$(strData$,I,1))
   Next
   cdWritten = CreateBank(4)
   
   fWrite = WriteFile2(lPortHandle,cdData,cbData,cdWritten,0)
   
   ; check if that worked
   If Not fWrite Then
      ; get error from kernel
      lErr = GetLastError()
      DebugLog "WriteFile failed ( err=" + Str$(lErr) + ")"
      
      ; make sure any comms errors are cleared
      tComStat  = CreateBank(40)
      lErrFLags = CreateBank(4)
      ClearCommError(lPortHandle,lErrFlags,tComStat)
      handleCommError(lPortHandle,lErrFlags)
   EndIf
   
   Return fWrite
End Function