Recent semiconductor design technology has been substantially developed that we can design a micro-system on a chip as well as implementing an application specific IC in an FPGA. SPARTAN-3E developed by Xilinx is equipped with an FPGA that holds as much as 500 thousand transistors connected with MicroBlaze softcore microprocessor bus system. In this paper, we discuss a method of implementing an embedded system using the SPARTAN-3E. We also explain the peripherals and the bus protocols and the expandability of this kind of embedded systems.