Transforming The Microprocessor Class: Expanding Learning Objectives With Soft Core Processors

The rapid evolution of semiconductor technology over the past four decades has fueled the information age and an era of ubiquitous computing. Furthermore, the exponential increase in the number of transistors available in integrated circuits has drastically changed the field of electrical and computer engineering. Computer Aided Design (CAD) tools allow systems engineers to work at higher-levels of abstraction to design increasingly more complex systems. Embedded system design has been a keystone course in electrical and computer engineering curricula. Following the migration from discrete components to programmable logic devices in introductory digital design courses we expect to see a similar, yet more selective, shift to the use of soft core processors in future microprocessor and embedded systems courses. Soft core processors and peripheral devices can readily be implemented on a programmable logic device, typically a Field Programmable Gate Array (FPGA), and can be customized with respect to system requirements. Off-the-shelf processors cannot offer a customized computer system or the ability to design user-specified hardware as part of a system-on-a-chip. These aspects are the most advantageous characteristics of the soft core approach to embedded systems. Students themselves will design their computing platform using only the necessary peripherals. They will define the memory system and assign addresses to memory mapped peripheral registers. They will analyze system performance based on hardware and software tradeoffs against a backdrop of the utilization of hardware resources, thus vastly increasing the design space they consider for their projects. In this paper we predict a shift in the pedagogical approach to teaching the microprocessor course from one that uses off the shelf processors to one that will include the teaching of the soft core processor. We support our claim by reviewing advances in the programmable logic industry from which these processors have emerged, outlining current soft core processor applications and trends in industry, detailing learning objectives for a soft corebased approach (patterned after the course we currently teach), and summarizing resources available to those interested in using soft core processors at their schools.