Interfacing Switch and LED with 8051

Interfacing Switch and LED with 8051

            This article is meant for beginners in the field of micro-controllers  When I started with micro-controllers as everyone I also need to learn how to interface a switch with micro-controller.

A switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another. A switch may be directly manipulated by a human as a control signal to a system, or to control power flow in a circuit.

A switch requires a pull-up or pull-down resistor to produce a definite high or low voltage when it is open or closed. A resistor placed between a digital input and the supply voltage is called a "pull-up" resistor because it normally pulls the pin's voltage up to the supply. 

Software Tools:

1.      RIDE Compiler (Evaluation version) 

2.      WINISP Down loader      (Free version ) 

Hardware:

1. P89C51

2. Push button switch

3. micro-controller board

Program:

#include<reg51.h>

sbit LED=P0^7; //port declaration

sbit SW1=P0^0;

sbit SW2=P0^1;

void main()

{

while(1)

{

if(SW1==0 || SW2==0) //if the SW1 or SW2 is pressed

{

LED=1;

}

else

LED=0;

}

}

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