# define the used CPU
  export CPU = nrf51
  export CPU_MODEL = nrf51x22xxab
  
  # define the default port depending on the host OS
  PORT_LINUX ?= /dev/ttyACM0
  PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
  
  # setup JLink for flashing
  export JLINK_DEVICE := nrf51822
  include $(RIOTMAKE)/tools/jlink.inc.mk
  
  # setup serial terminal
  include $(RIOTMAKE)/tools/serial.inc.mk