LED Flashing programming in Embedded C language


Sample code for LED Flashing using delay subroutine.
Following code can be using for 8051 and 8052 ICs like: 89c51, 89c52, 89s51, 89s52, 89c2051.

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#include <reg52.h>          // special function register declarations  
#include <stdio.h>          // prototype declarations for I/O functions
#define LEDPORT P2
void Delay(void);                 //Function prototype declaration
void main (void)
{
     while(1)                 //End less while so that program never ends 
     {
        LEDPORT = 0x55;           //01010101 binary
        Delay();
        LEDPORT = 0xaa;           //10101010 binary
        Delay();	
     }
}
void Delay(void)
{
     int i, j;
     for(i=0;i<10;i++)
     {
        for(j=0;j<10000;j++)
        {    
        }
     }
}
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Assembly code for LED Flashing

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		org 0000h
		jmp start

start:		mov p1,#FFh
		call delay
		mov p1,#00h
		call delay
		jmp start

delay:		mov r0,#10
del2:		mov r1,#250
del1:		mov r2,#250
		djnz r2,$
		djnz r1,del1
		djnz r0,del2
		ret
  end
;========================================================== LED interfacing program