Makefile.common

C_SRCS   = $(filter %.c, $(SRCS))
AS_SRCS  = $(filter %.S, $(SRCS))

C_OBJS   = $(C_SRCS:.c=.o)
AS_OBJS  = $(AS_SRCS:.S=.o)

OBJ_DIR  = obj
_OBJECTS = $(C_OBJS) $(AS_OBJS)
OBJECTS  = $(patsubst %,$(OBJ_DIR)/%,$(_OBJECTS))

DEPS     = $(OBJECTS:.o=.d)

CROSS    = avr
CC       = $(CROSS)-gcc
AS       = $(CROSS)-gcc
SIZE     = $(CROSS)-size
OBJCOPY  = $(CROSS)-objcopy

CFLAGS   = -Wall
CFLAGS  += -Os
CFLAGS  += -mmcu=$(MCU) -DF_CPU=$(FREQ)
CFLAGS  += -ffunction-sections -fdata-sections

ASFLAGS += $(CFLAGS)

LDFLAGS  = -Wl,-Map,$(OBJ_DIR)/$(TARGET).map
LDFLAGS += -Wl,--gc-sections

all: $(OBJ_DIR)/$(TARGET).hex

-include $(DEPS)

$(OBJ_DIR)/%.o : %.S
	@mkdir -p $(OBJ_DIR)
	$(CC) $(ASFLAGS) $(CPPFLAGS) -c -MM -MF $(patsubst %.o,%.d,$@) $<
	@sed -i 's/.*\.o/$(OBJ_DIR)\/&/' $(patsubst %.o,%.d,$@)
	$(AS) $(ASFLAGS) $(CPPFLAGS) -c -o $@ $<

$(OBJ_DIR)/%.o : %.c
	@mkdir -p $(OBJ_DIR)
	$(CC) $(CFLAGS) $(CPPFLAGS) -c -MM -MF $(patsubst %.o,%.d,$@) $<
	@sed -i 's/.*\.o/$(OBJ_DIR)\/&/' $(patsubst %.o,%.d,$@)
	$(CC) $(CFLAGS) $(CPPFLAGS) -c -o $@ $<

$(OBJ_DIR)/$(TARGET).elf : $(OBJECTS)
	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^

$(OBJ_DIR)/$(TARGET).hex : $(OBJ_DIR)/$(TARGET).elf
	$(SIZE) -C --mcu=$(MCU) $^
	$(OBJCOPY) -O ihex -j .text $^ $@ 

.PHONY: clean
clean:
	@rm -rf $(OBJ_DIR)