Atmel 328p AVR LED blink simple

ledBlinkSimple.c

/*
  sudo avr-gcc -Wall ledBlinkSimple.c -mmcu=atmega328p -o ledBlinkSimple.o
  sudo avr-objcopy -O ihex -R .eeprom ledBlinkSimple.o ledBlinkSimple.hex
  sudo avrdude -p atmega328p -c avrisp2 -U flash:w:ledBlinkSimple.hex -P /dev/ttyACM0
*/
#define F_CPU 1000000UL //Tell delay.h we're running the default 1 MHz

#include <avr/io.h>
#include <util/delay.h>

int main(void) {
  DDRC = 0xFF; 
  while(1) {
    PORTC = 0xFF; //all pins up
    _delay_ms(100); 
    PORTC= 0x00; //all pins down
    _delay_ms(100);
  }
}