The Hardware-Oriented Microprocessor Simulator, HOMS, Unveils the Secrets in Black Box Chips
Built around Arduino UNO modules with a controlling Arduino Mega 2560, this briefcase-housed simulator is a very unintegrated circuit.
UPDATE (8/16/2024): Associate professor Dr. Panayotis (Panos) Papazoglou has released an updated version of the Hardware-Oriented Microprocessor Simulator (HOMS), dubbed V.1B, which is designed to be easier to build.
"[It] now includes visual aids for setting contrast, brightness, etc.," Papazoglou says of the tweaked design. "The new touch-'n'-feel is more realistic. Includes also TFT color displays and a new GUI [Graphical User Interface] PC-based environment for easy programming. It is also simplified by using only two types of blocks and eight units in total."
The revised version is available on the same website as before.
Original article continues below.
Dr. Panayotis (Panos) Papazoglou, associate professor at the National and Kapodistrian University of Athens (NKUA), has designed a modular device that aims to teach about how microprocessors and microcomputers work: the Hardware-Oriented Microprocessor Simulator (HOMS).
"In this project, a fully working and mature educational tool for learning microprocessors is proposed for the very first time in the literature for higher education in the field of computer science and computer engineering," Papazoglou writes of the HOMS system. "The proposed educational tool [addresses] effectively every limitation of the previous versions, is based on open source hardware, and can be reproduced by everyone."
The HOMS system aims to provide insight into how an eight-bit microprocessor-based computer operates, and does so by breaking everything out into discrete modules. Each register and counter, for example, is given a dedicated two-digit seven-segment display, separate to the system's primary 2.4" TFT display. Behind each module is an Arduino microcontroller board — either an Arduino UNO or, for the control and display module, an Arduino Mega 2560.
The idea, Papazoglou explains, is to give students a physical object representing a given internal component of a simple microprocessor — rather than a solid black chip. The design is also customizable, he says: "The teacher or student can use any number or type of blocks for building the preferred microprocessor architecture. Based on the number and type of blocks, a teacher or student can test a prototype architecture or to expand an operation to smaller steps by using more blocks."
"The main advantage of the implemented HOMS tool," Papazoglou continues, "is the object-oriented approach and the open source hardware which gives the freedom to any developer not only to reproduce the same tool but also to implement the whole simulator using different blocks (with or without an LCD, buttons, etc). Note that the embedded software makes the difference."
The HOMS system is documented in full on Papazoglou's website, where the design is made available under the Creative Commons Attribution-NoCommercial-ShareAlike 4.0 license.