Switch and a LED with Atmega128 Breakout Revision as of 16:34, 5 April 2016 by Raghavendra (Talk | contribs) (diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Now we will control the LED depending on external input. In this tutorial we will interface a switch to one of the port pin and display its status on LED connected to other port.

Basics

For this tutorial we will a connect a switch to PORT C0 and LED to PORT B0 of Atmega128. W will configure PORT A0 as input to read the switch status and PORT C0 as outputto display the switch status on LED. Initially LED will be ON , when we press switch the LED will be OFF.
Refer the AVR I/O Register Configuration tutorial for basics of GPIO register configuration.

Hook Up

Code

	#include <avr/io.h>
	#include <util/delay.h>
	#define LED PB0
	#define SWITCH PC0
	int main()
	{
	DDRB = (1 << LED); // Configure PORTB as output to connect Leds
	DDRC = (0 << SWITCH); // Configure PORTC as Input to connect switches
	PORTC = (1 << SWITCH); // Enable The PullUps of PORTC.
	while(1)
	{
	while(((PINC) & (1<<SWITCH)) == 1) // Check the status of the switch
	{
	PORTB |= (1<<LED);
	}
	PORTB &= ~(1<<LED);
	}
	return 0;
	}

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Demo