Attiny85 beginner example – Flash an LED

The hello world of examples this time for an ATTINY85, although this should work with similar chips as well. We will connect the LED to pin 2 (PB3) and simply flash it on and off.

Here is our schematic

Schematic

Code

The code was written in Atmel Studio

#include <avr/io.h>
#define F_CPU 1000000UL
#include &lt;util/delay.h&gt;

// Define the I/O port to be used for the LED.
#define LED_PORT PB3

int main(void) {

// Set the LED port number as output.
DDRB |= (1 &lt;&lt; LED_PORT);

// Start infinite loop.
while (1)
{

// Set the LED bit to "1" - LED will be "on".
PORTB |= (1 &lt;&lt; LED_PORT);
// The delay function simply does N-number of "empty" loops.
_delay_ms(200);
// Set the LED bit to "0" - LED will be "off".
PORTB &amp;= ~(1 &lt;&lt; LED_PORT);
_delay_ms(400);
}

return (0);
}

And another way

#include <avr/io.h>
#define F_CPU 1000000UL
#include <util/delay.h>

// Define the I/O port to be used for the LED.
#define LED_PORT PB3

int main(void) {

 // Set the LED port number as output.
 DDRB |= (1 << LED_PORT);

 // Start infinite loop.
 while (1)
 {

 // Set the LED bit to "1" - LED will be "on".
 PORTB |= (1 << LED_PORT);
 // The delay function simply does N-number of "empty" loops.
 _delay_ms(200);
 // Set the LED bit to "0" - LED will be "off".
 PORTB &= ~(1 << LED_PORT);
 _delay_ms(400);
 }

 return (0);
}