{ **********************************************************************
  ** Program: S1DEB9.PAS             Version: 1.1- 17  February  1999 **
  ** Firm:      GRIFO(r)         Via  Dell'Artigiano 8/6              **
  **                          40016  San Giorgio di Piano (BO)        **
  **                          Tel. 051-892052  FAX  051-893661        **
  ** Developed by : Tassinari Enea                                    **
  **********************************************************************
  
  This program allows to display the led sliding from right to left and one
  from left to right. If you put the jumper j10 in 2-3 position, when there
  is the crossing of the two leds, the buzzer sound.   
  In order to make an easier visualization of the status lines, it is 
  necessary to get a 20 pins flat cable for connecting GPC(r)15R CN9 connector
  to TIO 16 CN1 connector, or DEB-01 CN15 connector. }

program S1DEB9;
{$C-} { disable the Ctrl+C }

const
CNT=$17; { Control and command register of the PPI 82C55 }
PDA=$14; { Data register of the A port }
PDB=$15; { Data register of the B port }
PDC=$16; { Data register of the C port }
RIT=100; { Delay of 100 ms }

var
INDIRIZZO:BYTE;
STATO:byte;
TASTO:char;
OUTPDA:integer;
OUTPDC:integer;

procedure INIZIALIZZAZIONE; 
{ Initialization of the control register of the 82C55 }
  begin 
   port[CNT]:=130;
  end;

  procedure SCRITTURA (STATO:byte; INDIRIZZO:byte);
{ Write on A-C port }
  
 begin                                         
   port[INDIRIZZO]:=STATO;
  end;

procedure BUZZER;
{ This procedure is used to produce one square wave for the buzzer sound. } 
 var 
 BIT:byte;  
 INDICE:integer;
 RITARDO:integer; 
  begin
   for INDICE:=1 to 500 do  { Loop for the square wave }
    begin
      BIT:=OUTPDC and 127; 
    { Read the status of the OUTPDC variable and sensibilize only bit 7. } 
      SCRITTURA(255-BIT,PDC);
      for RITARDO:=1 to 8 do; 
      BIT:=OUTPDC or 128;
     { Read the leds status and change only bit 7 (bit 7 always=1) } 
      SCRITTURA(255-BIT,PDC);
      for RITARDO:=1 to 8 do;    
    end;
  end;

begin {program main }
 clrscr;
 INIZIALIZZAZIONE;
 gotoxy(10,3);
 writeln('VISUALIZATION OF THE LEDS RUN ON A-C PORT IN PROGRESS');
 gotoxy(25,4); 
 write('Press any key for exit');
   begin 
     OUTPDA:=1;
     OUTPDC:=128;
        repeat
          begin
            SCRITTURA(255-OUTPDA,PDA);
            SCRITTURA(255-OUTPDC,PDC); 
            delay(RIT);
            if OUTPDA=128 then OUTPDA:=1
            { You can lighting in sequence the last and first LED. }
            else  OUTPDA:=OUTPDA shl 1;
            { You can shift in left direction the middle bits. } 
            if OUTPDC=1 then 
               begin
                BUZZER;
                OUTPDC:=128;
               end
            { You can lighting in sequence the firs and last LED. }
            else OUTPDC:=OUTPDC shr 1;              
            { You can shift in right direction the middle bits. }      
          end;
        until keypressed;
   end;  
 SCRITTURA(255,PDA);
 SCRITTURA(255,PDC);
 { Led off in the end time }
 read(kbd,TASTO);
end.