diff --git a/Makefile b/Makefile
index 32de8af..e391390 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,7 @@
 # Version
 ###########################################################################
 
-Makefile_Version := 1.0.2
+Makefile_Version := 1.0.3
 $(info ISE Makefile Version: $(Makefile_Version))
 
 ###########################################################################
@@ -39,7 +39,8 @@ endif
 
 TOPLEVEL         ?= $(PROJECT)
 CONSTRAINTS      ?= $(PROJECT).ucf
-BITFILE          ?= build/$(PROJECT).bit
+BUILD_DIR        ?= working
+BITFILE          ?= $(BUILD_DIR)/$(PROJECT).bit
  
 COMMON_OPTS      ?= -intstyle xflow
 XST_OPTS         ?=
@@ -82,10 +83,10 @@ else
 endif
 
 TEST_NAMES = $(foreach file,$(VTEST) $(VHDTEST),$(basename $(file)))
-TEST_EXES = $(foreach test,$(TEST_NAMES),build/isim_$(test)$(EXE))
+TEST_EXES = $(foreach test,$(TEST_NAMES),$(BUILD_DIR)/isim_$(test)$(EXE))
 
 RUN = @echo "\n\e[1;33m============ $(1) ============\e[m\n"; \
-	cd build && $(XILINX)/bin/$(XILINX_PLATFORM)/$(1)
+	cd $(BUILD_DIR) && $(XILINX)/bin/$(XILINX_PLATFORM)/$(1)
 
 # isim executables don't work without this
 export XILINX
@@ -104,7 +105,7 @@ $(foreach src,$(1),\
     $(eval filepath=$(word 2,$(lib_and_path))) \
     $(if $(filepath),,$(eval filepath=$(libname)) $(eval libname=work)) \
     $(eval $(2) += $(libname)) \
-    $(eval $(3) += $(filepath)) \
+    $(eval $(3) += ../$(filepath)) \
 )
 endef
 
@@ -120,25 +121,25 @@ $(eval $(call process_sources,$(VSOURCE),V_LIBS,V_PATHS))
 default: $(BITFILE)
 
 clean:
-	rm -rf build
+	rm -rf $(BUILD_DIR)
 
-build/$(PROJECT).prj: project.cfg
+$(BUILD_DIR)/$(PROJECT).prj: ../project.cfg
 	@echo "Updating $@"
-	@mkdir -p build
+	@mkdir -p $(BUILD_DIR)
 	@rm -f $@
 	@$(foreach idx,$(shell seq 1 $(words $(V_PATHS))),echo "verilog $(word $(idx),$(V_LIBS)) \"../$(word $(idx),$(V_PATHS))\"" >> $@;)
 	@$(foreach idx,$(shell seq 1 $(words $(VHD_PATHS))),echo "vhdl $(word $(idx),$(VHD_LIBS)) \"../$(word $(idx),$(VHD_PATHS))\"" >> $@;)
 
 
-build/$(PROJECT)_sim.prj: build/$(PROJECT).prj
-	@cp build/$(PROJECT).prj $@
-	@$(foreach file,$(VTEST),echo "verilog work \"../$(file)\"" >> $@;)
-	@$(foreach file,$(VHDTEST),echo "vhdl work \"../$(file)\"" >> $@;)
+$(BUILD_DIR)/$(PROJECT)_sim.prj: $(BUILD_DIR)/$(PROJECT).prj
+	@cp $(BUILD_DIR)/$(PROJECT).prj $@
+	@$(foreach file,$(VTEST),echo "verilog work \"../../$(file)\"" >> $@;)
+	@$(foreach file,$(VHDTEST),echo "vhdl work \"../../$(file)\"" >> $@;)
 	@echo "verilog work $(XILINX)/verilog/src/glbl.v" >> $@
 
-build/$(PROJECT).scr: project.cfg
+$(BUILD_DIR)/$(PROJECT).scr: ../project.cfg
 	@echo "Updating $@"
-	@mkdir -p build
+	@mkdir -p $(BUILD_DIR)
 	@rm -f $@
 	@echo "run" \
 	    "-ifn $(PROJECT).prj" \
@@ -148,14 +149,14 @@ build/$(PROJECT).scr: project.cfg
 	    "-top $(TOPLEVEL)" \
 	    "-ofmt NGC" \
 	    "-p $(TARGET_PART)" \
-	    > build/$(PROJECT).scr
+	    > $(BUILD_DIR)/$(PROJECT).scr
 
-$(BITFILE): project.cfg $(V_PATHS) $(VHD_PATHS) $(CONSTRAINTS) build/$(PROJECT).prj build/$(PROJECT).scr
-	@mkdir -p build
+$(BITFILE): ../project.cfg $(V_PATHS) $(VHD_PATHS) ../$(CONSTRAINTS) $(BUILD_DIR)/$(PROJECT).prj $(BUILD_DIR)/$(PROJECT).scr
+	@mkdir -p $(BUILD_DIR)
 	$(call RUN,xst) $(COMMON_OPTS) \
 	    -ifn $(PROJECT).scr
 	$(call RUN,ngdbuild) $(COMMON_OPTS) $(NGDBUILD_OPTS) \
-	    -p $(TARGET_PART) -uc ../$(CONSTRAINTS) \
+	    -p $(TARGET_PART) -uc ../../$(CONSTRAINTS) \
 	    $(PROJECT).ngc $(PROJECT).ngd
 	$(call RUN,map) $(COMMON_OPTS) $(MAP_OPTS) \
 	    -p $(TARGET_PART) \
@@ -167,13 +168,13 @@ $(BITFILE): project.cfg $(V_PATHS) $(VHD_PATHS) $(CONSTRAINTS) build/$(PROJECT).
 	@echo "\e[1;32m============ OK ============\e[m\n\n"
 	@echo "\e[1;33m============ Reports.. ===========\e[m\n"
 	@echo "\e[1;97m==== Synthesis Summary Report ====\e[m"
-	@echo "\e[1;35m ./build/$(PROJECT).srp\e[m\n"
+	@echo "\e[1;35m ./$(BUILD_DIR)/$(PROJECT).srp\e[m\n"
 	@echo "\e[1;97m======= Map Summary Report =======\e[m"
-	@echo "\e[1;35m ./build/$(PROJECT).map.mrp\e[m\n"
+	@echo "\e[1;35m ./$(BUILD_DIR)/$(PROJECT).map.mrp\e[m\n"
 	@echo "\e[1;97m======= PAR Summary Report =======\e[m"
-	@echo "\e[1;35m ./build/$(PROJECT).par\e[m\n"
+	@echo "\e[1;35m ./$(BUILD_DIR)/$(PROJECT).par\e[m\n"
 	@echo "\e[1;97m===== Pinout Summary Report ======\e[m"
-	@echo "\e[1;35m ./build/$(PROJECT)_pad.txt\e[m\n"
+	@echo "\e[1;35m ./$(BUILD_DIR)/$(PROJECT)_pad.txt\e[m\n"
 	
 
 
@@ -181,30 +182,30 @@ $(BITFILE): project.cfg $(V_PATHS) $(VHD_PATHS) $(CONSTRAINTS) build/$(PROJECT).
 # Testing (work in progress)
 ###########################################################################
 
-trace: project.cfg $(BITFILE)
+trace: ../project.cfg $(BITFILE)
 	$(call RUN,trce) $(COMMON_OPTS) $(TRACE_OPTS) \
 	    $(PROJECT).ncd $(PROJECT).pcf
 	@echo "\n\e[1;33m============ Reports.. ===========\e[m\n"
 	@echo "\e[1;97m===== Timing Summary Report ======\e[m"
-	@echo "\e[1;35m ./build/$(PROJECT).twr\e[m\n"
+	@echo "\e[1;35m ./$(BUILD_DIR)/$(PROJECT).twr\e[m\n"
 
 test: $(TEST_EXES)
 
-build/isim_%$(EXE): $(V_PATHS) $(VHD_PATHS) build/$(PROJECT)_sim.prj $(VTEST) $(VHDTEST)
+$(BUILD_DIR)/isim_%$(EXE): $(V_PATHS) $(VHD_PATHS) $(BUILD_DIR)/$(PROJECT)_sim.prj $(VTEST) $(VHDTEST)
 	$(call RUN,fuse) $(COMMON_OPTS) $(FUSE_OPTS) \
 	    -prj $(PROJECT)_sim.prj \
 	    -o isim_$*$(EXE) \
 	    work.$* work.glbl
 
-isim: build/isim_$(TB)$(EXE)
-	@grep --no-filename --no-messages 'ISIM:' $(TB).{v,vhd} | cut -d: -f2 > build/isim_$(TB).cmd
-	@echo "run all" >> build/isim_$(TB).cmd
-	cd build ; ./isim_$(TB)$(EXE) -tclbatch isim_$(TB).cmd
+isim: $(BUILD_DIR)/isim_$(TB)$(EXE)
+	@grep --no-filename --no-messages 'ISIM:' $(TB).{v,vhd} | cut -d: -f2 > $(BUILD_DIR)/isim_$(TB).cmd
+	@echo "run all" >> $(BUILD_DIR)/isim_$(TB).cmd
+	cd $(BUILD_DIR) ; ./isim_$(TB)$(EXE) -tclbatch isim_$(TB).cmd
 
-isimgui: build/isim_$(TB)$(EXE)
-	@grep --no-filename --no-messages 'ISIM:' $(TB).{v,vhd} | cut -d: -f2 > build/isim_$(TB).cmd
-	@echo "run all" >> build/isim_$(TB).cmd
-	cd build ; ./isim_$(TB)$(EXE) -gui -tclbatch isim_$(TB).cmd
+isimgui: $(BUILD_DIR)/isim_$(TB)$(EXE)
+	@grep --no-filename --no-messages 'ISIM:' $(TB).{v,vhd} | cut -d: -f2 > $(BUILD_DIR)/isim_$(TB).cmd
+	@echo "run all" >> $(BUILD_DIR)/isim_$(TB).cmd
+	cd $(BUILD_DIR) ; ./isim_$(TB)$(EXE) -gui -tclbatch isim_$(TB).cmd
 
 
 ###########################################################################