Project build for ATmega

main.c

#define F_CPU 16000000UL

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

int main (void)
{
    DDRB |= _BV(PB5);
    PORTB &= ~_BV(PB5);
    while (1)
    {
        if (PINB & (1 << PB5)) {
            PORTB &= ~_BV(PB5);
        } else {
            PORTB |= _BV(PB5);
        }
        _delay_ms(500);
    }
    return 0;
}

Makefile

MCU=m168p
MMCU=atmega168pa
DEVICE=avrisp2

.PHONY: all flash build download clean

all: build

flash: build download clean

build:
	avr-gcc -g -Os -mmcu=$(MMCU) -c main.c && avr-gcc -g -mmcu=$(MMCU) -o main.elf main.o && avr-objcopy -j .text -j .data -O ihex main.elf main.hex

download:
	avrdude -p $(MCU) -c $(DEVICE) -U flash:w:main.hex

clean:
	@rm -v *.hex *.o *.elf

erase:
	avrdude -p $(MCU) -c $(DEVICE) -e