WirelessHART is one of the latest communication standards that have enhanced functionality and robustness. The standard is ideal for applications in control and automation industry. In this work we present an implementation the TDMA state machine of the WirelessHART communication protocol on TinyOS operating system using the nesC language for the Telobs motes. The development was carried out using software reuse principle and involved comparing the state diagram description of the TDMA presented in WirelessHART with that of the time synchronized frequency hopping implementation that was already available for reuse. The work highlights the differences between the TSCH code and the WirelessHART specifications and builds upon the TSCH code to arrive at the WirelessHART TDMA state machine implementation.