LIB = $(obj)lib$(SOC).a
-COBJS += speed.o
-COBJS += timer.o
-COBJS += usb.o
-COBJS += usb_ohci.o
+COBJS-$(CONFIG_USE_IRQ) += interrupts.o
+COBJS-y += speed.o
+COBJS-y += timer.o
+COBJS-y += usb.o
+COBJS-y += usb_ohci.o
-SRCS := $(SOBJS:.o=.S) $(COBJS:.o=.c)
-OBJS := $(addprefix $(obj),$(SOBJS) $(COBJS))
+
+SRCS := $(SOBJS:.o=.S) $(COBJS-y:.o=.c)
+OBJS := $(addprefix $(obj),$(SOBJS) $(COBJS-y))
all: $(obj).depend $(LIB)