International Journal of Recent Trends in Electrical & Electronics Engg., Sept 2011. ©IJRTE ISSN: 2231-6612 Volume 1, Issue 1, pg: 15-24 | 15 Custom Single-Purpose Event Processor Design: For Low Power WSN Node KSHITIJ SHINGHAL 1 , ARTI NOOR 2 , NEELAM SRIVASTAVA 3 , RAGHUVIR SINGH 4 1 Department of E&C Engg., M.I.T, Moradabad, India. 2 Department of M. Tech. VLSI Design Group, C-DAC, Noida, India. 3 Department of E&C Engg., I.E.T, Lucknow, India. 4 Academic Advisor, Shobhit University, Merrut, India. ABSTRACT A basic processor consists of a controller and a data path. The datapath stores and manipulates a system’s data. The data in the case of WSN node is the data acquired by the sensors of node after measuring the ambient conditions to be stored, processed and compressed for transmission; controller is capable of moving data through datapath. The combinational and sequential logic design techniques are applied to build a controller and datapath for a custom designed single-purpose event processor for WSN Node. Such custom designed single-purpose event processor results in several benefits in terms of faster performance, smaller size lower power consumption. WSN Node consists of sensors, a radio circuit a processor/microcontroller and some sort of power source. Event processor is custom designed, simulated, tested and implemented for single purpose application i.e. WSN Node using VHDL. Active HDL is used for simulation; to examine the various trade offs of using general purpose versus single purpose processor to implement necessary WSN node functionality. KEYWORDS: Datapath, VHDL, WSN Node, Active HDL, Custom Single purpose event processor. I. INTRODUCTION Wireless Sensor Networks (WSN) is rapidly becoming popular and finding use in many areas of day to day life. The sensor nodes are able to monitor a wide variety of ambient conditions that include the following: flow, temperature, pressure, humidity, moisture, noise levels, mechanical stress, speed, etc. There are numerous areas for the deployment of wireless sensors: physiological monitoring, habitat monitoring, precision agriculture, forest fire detection, nuclear, chemical, biological attack detection, military, transportation, disaster relief, and environmental monitoring (air, water, and soil chemistry) etc. The basic components of a sensor node are shown in figure 1. A typical sensor node consist of a sensing unit having sensor for sensing ambient conditions, a processing unit having a CPU for processing collected data and a transmission unit having transceiver for communication with base. Other units depending upon application are position finding system and a mobilizer all these units powered by a power unit sometimes connected to a power generator. Since maximum network life is desired and the amount of energy available for each node is finite (nodes are typically battery powered), low power implementations are a required for longer life of WSN node. In the proposed design a custom single purpose event processor is designed such as to meet the specific requirements of the processing unit of atypical processor node. Designing is done by determining the systems architecture for WSN Node, and then mapping the functionality through behavioral and structural description to that architecture. Designing a custom designed single-purpose event processor may result in increase in NRE cost and time to market as well as it will result in reduction in power consumption, number of transistor on chip and number of clock cycles ( increasing speed ).