This paper presents a method for mapping software state machines used in protocol stacks and communication layers directly to hardware communication devices using their specifications. The proposed method can handle power modes and timing constraints imposed by hardware devices in order to optimize the software code running on top of the device. This property allows the use of the hardware device in its lowest power consumption mode while making sure that real time constraints are met. To validate the merit of the proposed method, the generated code and power consumption gain, we evaluate the optimizations that can be done on a BMAC medium access control layer used in wireless sensor networks using a large scale experimental testbed. The results show that an average energy consumption gain of up to 60% at the radio level can be achieved.