// ATtiny85 Blink!
#include <avr/io.h>

#define LED_PIN PB4

void setup() {
  // pinMode(LED_PIN, OUTPUT); // arduino code
  DDRB |= (1 << LED_PIN); //pinMode as output
}

void loop() {
  // digitalWrite(LED_PIN, HIGH); // arduino code
  PORTB |= (1 << LED_PIN); // turn on LED
  delay(1000);
  // digitalWrite(LED_PIN, LOW); // arduino code
  PORTB &= ~(1 << LED_PIN); // turn on LED
  delay(1000);
}