led blinking-8051

LED Blinking program in 8051:

8051 is a 8-bit micro-controller. i.e.,it data  bus size is 8-bit  so that each port in 8051 having 8 pins and having 4 ports Port-0,Port-1,Port-2,Port-3

this example showing the led blinking for Port 1

#include <reg52.h>//header file for 8051 or 8052
void delay(int ch)
{
int i=0,j=0;
for(i=0;i<ch;i++)
{
    for(j=0;j<1275;j++)
    {
    }
}
}
void main()
{
while(1)
{
    P1=0x00;
    delay(20);
    P1=0xff;
    delay(20);
}   
}


here while(1) is a continues loop (infinity loop)

P1=0x00; means all pins are active low that means zero Volts
P1=0xff; means all pins are active high that means 5 Volts

we are providing a delay of  200 millisec for ON and OFF state

below video shows every thing