Tutorial AT8951 with Proteus : Driving LED

Dear al hand
In first tutor , we want to drive seven led (LED as out put) with AT89051 mic.

1. First we must draw the circuit below(click the image to enlarge and download (in proteus file)) :

Fig.1 : Driving LED

We use P3 port as out port, connect this port with seven led in common cathode configuration. So if we want activate a led, we must send '0' to the coresponding port.

Below is the program for driving led turning ON two group led alternatelly:

Org 0h

Start :

Mov P3,#000001111B ; LED p3.4---P3.7 ON

Acall Ldelay ; call Ldelay sub

Mov P3,#11110000B ; P3.0---P3.3 ON

Acall Ldelay;

Sjmp Start; jump to start

; ----------------

; Sub Rutine delay

;-----------------

Delay : Mov R0, #0FFh ; fill RO reg with FF

Delay1:

Djnz R0,Delay1 ; decrement R0 and if not zero jum to delay1

Ret ; come back to the adres affter ACALL delay instruction

; ----------------

; Sub Rutine Ldelay

;-----------------

Ldelay : Mov R1, #0FFh ; fill R1 reg with FF

Ldelay1:

Acall Delay ;

Djnz R1,Ldelay1 ; decrement R0 and if not zero jum to delay1

Ret ; come back to the adres affter ACALL delay instruction

Ret

Ldelay sub is used for hold one group led in on condition; after delay time elapsed, another led group will turn on. Clik for download asm file.

We can program this circuit with C language :
# include
Delay( long int d)
{ //delay subs
long int i;
for (i=0; i<=d; i++) {} }// end delay sub unsigned char j,k; main() { do {k= 1; for (j=0;j<=7;j++)// repeat for seven time { P3= 0xFF-k; // turning on led k delay(10000); k=k*2;// left shifting }o for (j=0;j<=7;j++)// repeat for seven time P3= 0xFF-k; // turning on led k delay(10000); k=k/2;// right shifting } //end do } while (1);//main loop }