5.1. Simple Experiment with LED - Serial Port

In this experiment we will show you how easy to transfer data serially. In this experiment we used a converter serial to parallel that we build up by using microcontroller chip. Data will be transfered serially from computer to LEDs board, as shown in picture bellow.

Delphi Programming ( Download file ex511.zip )

a. Puts 1 Edit Components, 1 Timer and label on Form, as shown in picture bellow. Configure Object Inspector for Timer1 as Enabled = True, Interval = 1000 ms, as shown in the picture bellow.

var
 data,status:byte;
const
 base = $3f8;{base address port serial}
 lcr = 3; {line control register}
 dll = 0; {divisor lacht low byte}
 dlh = 1; {divisor lacht high byte}
 lsr = 5; {line status register}

implementation

{$R *.DFM}

Procedure Initserial;
begin
    asm
        mov dx,base+lcr; {address line control register}
        mov al,$80 ; {10000000b = access bit divisor lacht}
        out dx,al
;
        mov dx,base+dll; {address divisor lacht low byte}
        mov al,$30 ; {DLLB = 30h}
        out dx,al
;
        mov dx,base+dlh; {address divisor lacht high byte}
        mov al,$00 ; {DLLH = 00h}
        out dx,al
;                          {Pada saat ini Port serial}
;                          {memp.baud rate = 2400 bps}
        mov dx,base+lcr; {address line control register}
        mov al,$03 ;     {00000011b =}
        out dx,al ;         {bit 7=0, access to Rx buffer & Tx
;                           {bit 6=0, set break disable
;                           {bit 5-4-3=000, no parity
;                           {bit 2=0, one stop bit
;                           {bit 1-0=11,data lenght 8 bit}
        end;
end;


Procedure Send_Data_Serial;
begin
    asm
        mov dx,base
        mov al,data
        out dx,al
    end
end;

procedure TStoP.Timer1Timer(Sender: TObject);
begin
  repeat
    asm
      mov dx,base+lsr ; {address line status register }
      in al,dx
      and al,$20 ; {00100000b =not masking bit 5}
      mov status,al ; {bit5=Empty Transmitting holding reg}
    end;
  until status = $20; { If ETHR = 1 then data ready tobe send }
  data:=strtoint(edit1.text);
  Send_Data_Serial;
end;

c. To run the program, you can hits F9 or RUN menu, and then you will show a picture as shown bellow, and try to simulate the program by writing a data on edit1 with range value 0 .. 255 in decimal.

NEXT

Free Software
Delphi

Lesson 1
Delphi Programming
1.1. IDE Delphi
1.2. Component

Lesson 2
Printer Port / LPT
1.1.Basic
1.2.Address
1.3.Port Register
1.4.8 Bit Data Input
1.5.Test Circuitry
1.6.Assignment

Lesson 3
Printer Port / LPT
Experiments
3.1.LED
3.2.Swicht
3.3.Motor Stepper
3.4.DAC
3.5.ADC
3.6.Graph Display

Lesson 4
Serial Port
4.1.Basic
4.2.Hardware
4.3.Port Register

Lesson 5
Serial Port Experiments
5.1.LED
5.2.Stepper Motor
5.3.Swicht
5.4.ADC

Lesson 6
Game Port
Joy Stick
6.1. Basic
6.2. Experiments