Program Serielle_Schnittstelle;
Uses Dos,PortCrt;


var  Vout,Vin,Ref,D,B:Real;
     i,a,x,xx: Byte;
     adresse,zeichen: String;
     BA : word;


Begin
     BA:=MEMW[$0040:$0000];
     clrscr;

     Repeat
     B:=2048;
     Vout:=0;
     Ref:=5.0;
     adresse:='111101110001';
     For i:=1 to 12 do Begin
     x:=Port[BA+4];
     xx:=($FE and x);
     Port[BA+4]:=xx;
     zeichen:=copy(adresse,13-i,1);
     IF zeichen='0' then
     Begin
          Port[BA+4]:=($FD and Port[BA+4]);
     end
     else
     Begin
          Port[BA+4]:=($2 or Port[BA+4]);
     End;
     Port[BA+4]:=($1 or Port[BA+4]);

     IF (Port[BA+6] and 16 ) = 16 then
     Begin
          D:=0;
     End
     Else
     Begin
          D:=1;
     End;

     Vout:=Vout+(D*B);
     B:=B/2;
     End;

     Port[BA+4]:=($FD and Port[BA+4]);
     Port[BA+4]:=($2 or Port[BA+4]);
     Delay(20);
     Vin:=(Vout/4091)*Ref;
     Writeln(Vin:6:6,' Volt');
     Delay(800);
     until keypressed;
End.