add uf2 target for uf2 bootloader board: metro m0/m4 feather nrf52840

examples/make.mk

@@ -12,6 +12,7 @@ MKDIR = mkdir
 SED = sed
 CP = cp
 RM = rm
+PYTHON ?= python
 
 # Select the board to build for.
 ifeq ($(BOARD),)

examples/rules.mk

@@ -43,6 +43,8 @@ endif
 .DEFAULT_GOAL := all
 all: $(BUILD)/$(BOARD)-firmware.bin size
 
+uf2: $(BUILD)/$(BOARD)-firmware.uf2
+
 OBJ_DIRS = $(sort $(dir $(OBJ)))
 $(OBJ): | $(OBJ_DIRS)
 $(OBJ_DIRS):
@@ -60,6 +62,11 @@ $(BUILD)/$(BOARD)-firmware.hex: $(BUILD)/$(BOARD)-firmware.elf
 	@echo CREATE $@
 	@$(OBJCOPY) -O ihex $^ $@
 
+UF2_FAMILY ?= 0x00
+$(BUILD)/$(BOARD)-firmware.uf2: $(BUILD)/$(BOARD)-firmware.hex
+	@echo CREATE $@
+	$(PYTHON) $(TOP)/tools/uf2/utils/uf2conv.py -f $(UF2_FAMILY) -c -o $@ $^
+
 # We set vpath to point to the top of the tree so that the source files
 # can be located. By following this scheme, it allows a single build rule
 # to be used to compile all .c files.