Teaching digital logic design using a tape recorder simulator

This paper describes two implementations of a tape recorder simulator. One is based on hard-wired logic and the other on microcomputer programmed logic approach. Both implementations are compared and evaluated for such points as flexibility, speed, power and space requirements, and cost. The purpose of this paper is to introduce students of digital logic design to the problems of selecting a suitable implementation based on software and hardware requirements, and system constraints. This is to teach students how to recognize which problem should be implemented in hardware and which problem should be implemented in software, or when and how to split between hardware and software. By implementing both methods themselves, students get a hands-on experience in several hardware design techniques such as asynchronous state machine (ASM), EPROM programming, address decoding, and input/output port interfacing.