Using a radio board with Contiki-OS on lpc1347 mcu
You have to use Smart RF studio that's made available by TI. You have to type whatever the settings you want into it in a very generic sense. Then it creates several header files for you. These header files contain the register programing part as well as some APIs to call from your MCU. 

If you youtube, there is a video done  by a guy who demonstrates this for TI RTOS. However, you can use the very same method for controlling the RF transceiver via an MCU too.