Semicustom ASIC design facility based on logic cell arrays

Abstract

Application-specific integrated circuits (ASICs) are an increasingly important option for electronic systems designers, primarily as a result of rapid advances in CAD and manufacturing technology. As a result there is now a need to include ASIC design methodologies and considerations in undergraduate and postgraduate experience courses in electronic engineering. The paper describes a semicustom design laboratory set-up for teaching such a course at the University of Strathclyde. The main technology chosen for design exercises is the logic cell array (LCA). The unique feature of this device is that its configuration is determined by the contents of an on-chip static memory. This means that the device may be reconfigured an unlimited number of times, which makes it very economical and particularly attractive for educational use. Furthermore, field-programmable semicustom devices such as the LCA allow design exercises to be taken from the concept stage to ‘working silicon’ in a timescale that is much shorter than other ASIC alternatives. The paper outlines a sequence of design procedures performed in a typical design laboratory. In particular, it describes a low cost LCA prototyping board designed to act as a verification tool for LCA-based circuit development.