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THIS IS THE Borland Turbo Pascal unit for Driving LED display through parallel port
unit DisPara;
interface
type TPortArray = array[0..4,0..6] of byte;
TScanLine = array[0..6] of 0..1;
TScreenArray = array[0..4,0..6] of 0..3;
const NumberImagesArray:
array[$0..9,0..4,0..4] of byte=
(((0,(0),1,0,0),
(0,(1),0,1,0),
{0} (0,(1),0,1,0),
(0,(1),0,1,0),
(0,(0),1,0,0)),
((0,(0),1,0,0),
(0,(1),1,0,0),
{1} (0,(0),1,0,0),
(0,(0),1,0,0),
(0,(0),1,0,0)),
((0,(0),1,0,0),
(0,(1),0,1,0),
{2} (0,(0),0,1,0),
(0,(0),1,0,0),
(0,(1),1,1,0)),
((0,(1),1,0,0),
(0,(0),0,1,0),
{3} (0,(0),1,0,0),
(0,(0),0,1,0),
(0,(1),1,0,0)),
((0,(1),0,1,0),
(0,(1),0,1,0),
{4} (0,(1),1,1,0),
(0,(0),0,1,0),
(0,(0),0,1,0)),
((0,(1),1,1,0),
(0,(1),0,0,0),
{5} (0,(1),1,0,0),
(0,(0),0,1,0),
(0,(1),1,0,0)),
((0,(0),1,1,0),
(0,(1),0,0,0),
{6} (0,(1),1,0,0),
(0,(1),0,1,0),
(0,(0),1,0,0)),
((0,(1),1,1,0),
(0,(0),0,1,0),
{7} (0,(0),1,0,0),
(0,(0),1,0,0),
(0,(0),1,0,0)),
((0,(1),1,1,0),
(0,(1),0,1,0),
{8} (0,(1),1,1,0),
(0,(1),0,1,0),
(0,(1),1,1,0)),
((0,(0),1,0,0),
(0,(1),0,1,0),
{9} (0,(0),1,1,0),
(0,(0),0,1,0),
(0,(1),1,0,0)));
DataPortActiveArray:TPortArray =(($3F,$5F,$6F,$77,$7B,$7D,$7E),
($3F,$5F,$6F,$77,$7B,$7D,$7E),
($3F,$5F,$6F,$77,$7B,$7D,$7E),
($3F,$5F,$6F,$77,$7B,$7D,$7E),
($BF,$DF,$EF,$F7,$FB,$FD,$FE));
CtrlPortActiveArray:TPortArray =(($0A,$0A,$0A,$0A,$0A,$0A,$0A),
($09,$09,$09,$09,$09,$09,$09),
($0F,$0F,$0F,$0F,$0F,$0F,$0F),
($03,$03,$03,$03,$03,$03,$03),
($0B,$0B,$0B,$0B,$0B,$0B,$0B));
DataPort=$378; {Base addres of parallel port}
CtrlPort=DataPort+2;
var LastValueOfCtrlPort:byte;
UsedForBlinking:longint;
Procedure CellOn(xk,yk:byte);
Procedure HorizontalScan(EnteringLine:TScanLine;EnteringRow:byte);
Procedure TheWorldIsYoursScan(EnteringArray:TScreenArray);
Procedure DisplayOff;
implementation
Procedure CellOn(xk,yk:byte);
{Give it coordinates of point you want to be turned on. That diode would
be lit and every other would be turned off. Appropriate for aplications like
sound osciloscopes, mouse pointers or simple brick and ball game. If you
want diodes to shine better use the HorizontalScan}
var WriteCtrl,WriteData:byte;
begin
WriteData:=DataPortActiveArray[yk,xk];
WriteCtrl:=CtrlPortActiveArray[yk,xk];
if WriteCtrl=LastValueOfCtrlPort then
asm
mov dx,DataPort
mov al,WriteData
out dx,al
end
else
asm
mov dx,DataPort
mov al,WriteData
out dx,al
add dx,2
mov al,WriteCtrl
out dx,al
end;
LastValueOfCtrlPort:=WriteCtrl;
end;
Procedure HorizontalScan(EnteringLine:TScanLine;EnteringRow:byte);
{Give it a variable of TScanLine type(array [0..6] of 0..1]) 0 for OFF,
1 for ON, and row you want to be lit.Turns on only EnteringRow leaving
others rows off}
var i,WriteData,WriteCtrl:byte;
begin
WriteData:=$7F;
WriteCtrl:=CtrlPortActiveArray[EnteringRow,0];
for i:=0 to 6 do
begin
if EnteringLine[i]=1 then
WriteData:=WriteData and DataPortActiveArray[EnteringRow,i];
end;
if EnteringRow=4 then WriteData:=WriteData or $80;
asm
mov dx,CtrlPort
mov al,WriteCtrl
out dx,al
sub dx,2
mov al,WriteData
out dx,al
end;
end;
Procedure TheWorldIsYoursScan(EnteringArray:TScreenArray);
{Whoooow-Multimedia- it turns on, off or blinks one or more diodes depending}
{on the value of element in EnteringArray: }
{0-turn of 1-turn on 2-blinking 3-not implemented }
{experiment with UsedForBlinking to adjust it for your computer speed }
var i,j,WriteData,WriteCtrl:byte;
begin
WriteCtrl:=CtrlPortActiveArray[0,0];
inc(UsedForBlinking);
If UsedForBlinking>1000 then UsedForBlinking:=0; {experiment with different values }
for i:=4 downto 0 do
begin
WriteData:=$7F;
for j:=0 to 6 do
begin
if EnteringArray[i,j]=1 then
WriteData:=WriteData and DataPortActiveArray[i,j];
if EnteringArray[i,j]=2 then
if (UsedForBlinking mod 4000)<250 then {experiment with different values}
WriteData:=WriteData and DataPortActiveArray[i,j]
else
WriteData:=WriteData or (1 shl j);
WriteCtrl:=CtrlPortActiveArray[i,0];
end;
if i=4 then WriteData:=WriteData or $80;
asm
mov dx,CtrlPort
mov al,WriteCtrl
out dx,al
sub dx,2
mov al,WriteData
out dx,al;
end;
end;
end;
Procedure DisplayOff;
{Turns DisplayOff thus saving your paralel port from unnecessery power }
{disipation. Use it on the begining and end of your application. }
begin
Port[DataPort]:=$7F;
Port[CtrlPort]:=$0B;
end;
begin
UsedForBlinking:=0;
LastValueOfCtrlPort:=0;
end.
end.
Author: Aleksandar Masnikosa October '97
E-mail:masnikosa@yahoo.com