(* Release 3.10 *)
(*-------------------------------------------------------------------------*
*                                                                          *
*  RS232.DEF - COMMS Toolkit interrupt-driven serial I/O handler           *
*                                                                          *
*  COPYRIGHT (C) 1988..1992 Clarion Software Corporation.                  *
*  All Rights Reserved                                                     *
*                                                                          *
*--------------------------------------------------------------------------*)

DEFINITION MODULE RS232;
  CONST
    XOFF                = CHR(19);
    XON                 = CHR(17);

  TYPE
    PortNos             = [1..4];
    Bits                = [5..8];
    Stops               = [1..2];
    ParityCodes         = (None,Odd,dontUse1,Even,dontUse2,Mark,dontUse3,Space);
    FlowControls        = (NoFlowControl,XonXoff,RtsCts);
    TxHookProc          = PROCEDURE(VAR ARRAY OF CHAR,VAR CARDINAL);
    RxHookProc          = PROCEDURE(VAR CHAR);

  VAR
    Base,IntLevel       : CARDINAL;
    TxHook              : TxHookProc;
    RxHook              : RxHookProc;
    Hooked              : BOOLEAN;

  PROCEDURE SelectPort(Port:PortNos);
    (* Change serial port being used. Defaults to COM1. This disables    *)
    (* any previously installed interrupt handler, so Install will need  *)
    (* to be called again.                                               *)

  PROCEDURE InitPort(Baud:CARDINAL;DataBits:Bits;StopBits:Stops;Parity:ParityCodes);
    (* Initialise serial hardware                                        *)

  PROCEDURE SetFlowControl(Which:FlowControls);
    (* Select kind of flow control required - defaults to RTS/CTS        *)

  PROCEDURE Install;
    (* Install interrupt handlers                                        *)

  PROCEDURE CarrierDetect():BOOLEAN;
    (* True if Carrier (DCD) signal is asserted                          *)

  PROCEDURE UnInstall;
    (* Uninstall serial interrupt handler - forces line drop             *)

(*# save, call(o_a_copy => off) *)
  PROCEDURE SerialWrite(b:ARRAY OF CHAR; Lnth:CARDINAL);
    (* Copy "Lnth" characters from the array to the transmitter ring buffer *)
(*# restore *)

  PROCEDURE SerialRead(VAR c:CHAR;t:CARDINAL):BOOLEAN;
    (* Attempt to read a char from the serial port, timing out after "t" *)
    (* tenth/seconds. "t" may be zero, in which case it returns          *)
    (* immediately. The function result is TRUE if a char was read.      *)

  PROCEDURE FlushInBuf;
    (* Flushes the input buffer of all waiting characters.               *)

  PROCEDURE SetBreak(Tenths:CARDINAL);
    (* Assert break signal for the specified number of tenth/secs        *)

  PROCEDURE AddTxHook(Hook:TxHookProc;VAR OldHook:TxHookProc);
  PROCEDURE AddRxHook(Hook:RxHookProc;VAR OldHook:RxHookProc);
    (* Adds a new hook to the chain and returns the address of the hook  *)
    (* to chain to at the end of the new hook.                           *)
    (* N.B. - Remember not to chain if OldHook = NIL                     *)

END RS232.