CC=avr-gcc
CFLAGS=-Wall -Os -DF_CPU=$(F_CPU) -mmcu=$(MCU)
MCU=atmega328p
F_CPU=16000000UL

OBJCOPY=avr-objcopy
BIN_FORMAT=ihex

PORT=/dev/ttyUSB0
BAUD=115200
PROTOCOL=arduino
PART=$(MCU)
AVRDUDE=avrdude -F -V -D
# -v -v -v

PROG=main

RM=rm -f

.PHONY: all
all: ${PROG}.hex

${PROG}.hex: ${PROG}.elf

${PROG}.elf: ${PROG}.s

${PROG}.s: ${PROG}.c

.PHONY: clean
clean:
	$(RM) ${PROG}.elf ${PROG}.hex ${PROG}.s

.PHONY: program
program: ${PROG}.hex
	$(AVRDUDE) -c $(PROTOCOL) -p $(PART) -P $(PORT) -b $(BAUD) -U flash:w:$<

.PHONY: upload
upload: ${PROG}.hex
	$(AVRDUDE) -c $(PROTOCOL) -p $(PART) -P $(PORT) -b $(BAUD) -U flash:w:download.hex:i

.PHONY: download
download: ${PROG}.hex
	$(AVRDUDE) -c $(PROTOCOL) -p $(PART) -P $(PORT) -b $(BAUD) -U flash:r:download.hex:i

%.elf: %.s ; $(CC) $(CFLAGS) -s -o $@ $<

%.s: %.c ; $(CC) $(CFLAGS) -S -o $@ $<

%.hex: %.elf ; $(OBJCOPY) -O $(BIN_FORMAT) -R .eeprom $< $@