{ **********************************************************************
  ** Program: S1DEB7.PAS             Version: 1.1- 8  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 two way direction of the led in ON
  tatus according to the position of switch 1 of the dip switch.
  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 S1DEB7;
{$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
STATO:byte;
TASTO:char;
VAL:integer;
SWC:integer;
RIS:integer;

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

function LETTURA (INDIRIZZO:integer):byte;
{ Read the dip switch status } 
 begin
   LETTURA:=port[INDIRIZZO];
 end; 


procedure SCRITTURA (STATO:integer);
{ Write on A-C port }

var 
BYTEL,BYTEH:byte;  
  
 begin
   BYTEL:=STATO and $FF; 
   { Write into BYTEL variable only the low byte value of the contents of the 
     STATO variable }
   BYTEH:=(STATO and $FF00) shr 8; 
   { Write into BYTEH variable only the high byte value of the contents of the 
     STATO variable. The value came shift of 8 position in right direction so 
     you can see the BYTEH contents like low byte value. }                                         
   port[PDA]:=BYTEL;
   port[PDC]:=BYTEH;
  end;

begin {program main }
 clrscr;
 INIZIALIZZAZIONE;
 gotoxy(10,3);
 writeln('VISUALIZATION OF THE LED RUN ON A-C PORT IN PROGRESS');
 gotoxy(25,4); 
 write('Press any key for exit');
 gotoxy(6,6);
 write('Change the switch 1 position of the dip switch to inverte the run');
   begin 
     SCRITTURA($FFFF); { Led of A-C port in OFF }
     SWC:=LETTURA(PDB);
     RIS:=SWC and 1; { Sensibilize only switch 1 of the dip switch }
     if RIS=0 then VAL:=1 
     { The switch 1 reading involve the lighting of the firs or last LED. } 
     else VAL:=$8000; 
        repeat
          begin
            SCRITTURA($FFFF-VAL); 
            delay(RIT);
            SWC:=LETTURA(PDB);
            { Read the B port }
            RIS:=SWC and 1;
            { Mask the switch }
             if RIS=0 then
              begin
                if VAL=$8000 then VAL:=1 
                { You can lighting in sequence the last and first LED. }
                else VAL:=VAL shl 1;            
                { You can shift in left direction the middle bits. } 
              end  
             else 
              begin
               if VAL=1 then VAL:=$8000
               { You can lighting in sequence the firs and last LED. }
               else VAL:=VAL shr 1;
               { You can shift in right direction the middle bits. }
              end 
          end;
        until keypressed;
   end;  
 SCRITTURA($FFFF); { Led OFF in the end time. }
 read(kbd,TASTO);
end.