USES
  Crt;

CONST
  ADDRESS : WORD = $350;        { The Base address of the watchdog board. }

    procedure CtrMode(cntr,mode:byte);
    var ctrl:byte;
    begin
	    ctrl := (cntr shl 6) or $30 or (mode shl 1);
	    port[ADDRESS+3] := ctrl;
    end;

    procedure LoadCtr(c,val:integer);
    begin
	    port[ADDRESS+c] := lo(val);
	    port[ADDRESS+c] := hi(val);
    end;

{
******************************************************************************
PROCEDURE set_counter
Purpose: This procedure performs the setup operations on the 82C54 counter/
	 timer chip.
******************************************************************************
}
PROCEDURE set_counter;
VAR
  temp,control_word : BYTE;
BEGIN
  temp:=port[ADDRESS+7];
  CtrMode(0,3);         {program the counters for the REQUIRED modes}
  CtrMode(1,2);
  CtrMode(2,1);
  LoadCtr(0,-1);        {-1 is full load value, long reset and high granular}
  LoadCtr(1,10);
END; { End set_counter }


VAR
  read_back : BYTE;
  loop : WORD;
  ch : CHAR;
  aborted : boolean;
BEGIN
  clrscr;
  writeln('Pascal Sample #1: Use Of Counter/Timer Chip with Watchdog');
  writeln('This program demonstrates how to program the 82C54 counter/timer');
  writeln('chip on the Watchdog Timer board.  The Watchdog address should be set');
  writeln('to 350 hex.  A keystroke will stop the program.');
  writeln;
  writeln('Press any key to start.');
  ch := readkey;                        { Grab keystroke. }

  set_counter;          { programs counters }

  port[ADDRESS+7] := 0; { Starts counters counting }
  for loop := 1 to 1000 do
    begin
      CtrMode(1,2);
      LoadCtr(1,10);    {prompt counter 1--don't need to prompt 0}
      Writeln('Updating counter 1.  Loop number : ', loop);
      GotoXY(1, 7);
    end;

  writeln;
  writeln('Waiting for timeout . . .');

  aborted := false;
  repeat
    read_back := port[ADDRESS+4];  { load control value }
    aborted := KeyPressed;
  until ((aborted) OR ((read_back AND 128) = 0));  { check for bit 0 }

  writeln;
  if (aborted) then writeln('Timeout aborted!') else
     writeln('Watchdog timed out successfully.');
END.