A rapid prototyping environment for teaching digital logic design

Digital integrated circuit design serves as a crucial required course for students majoring in electronic science and technology. This subject combines theoretical knowledge with practical applications, playing a key role in establishing a strong foundation for students’ academic and career growth. Guided by the OBE concept, the reform of digital integrated circuit design aims to transcend traditional limitations, explore more efficient and high-quality teaching methods, and cultivate outstanding talents according to predefined goals, enabling them to meet job market demands and adapt to industry changes. To enhance the training model for professional talents in electronic science and technology and support the long-term development and planning of students, this approach achieves multiple objectives simultaneously. Consequently, this paper explores the essence of the OBE concept and provides an in-depth analysis of the current state and potential reform directions for the digital integrated circuit design course, aiming to offer valuable insights for educators on the front lines.

This paper presents a project based teaching experience in an advanced digital systems design course with emphasis on design methodologies and laboratory assignments. Projects are the core of the practised teaching methodology and are structured in a pedagogical format according to the course programme. The use of the FPGA technology as the most suitable implementation technology for digital design teaching purposes is discussed. The course structure, oriented to the development of real working digital systems, challenges the students and increases their motivation. This way, the learning process is improved and the classes are more productive. A laboratory development infrastructure based on a FPGA device, used to implement a real-time video processing system, is presented. Examples of laboratory projects implemented with this infrastructure in a recent course edition are also presented.

A new distance learning system, integrating a top-down design support system and a multi-user/multi-test-bed remote laboratory system for digital circuit hardware design and implementation course, is realized. The proposed system employs the hardware description language (VerilogHDL) for the design database and FPGAs for design implementation test-beds. Students using this remote laboratory system at remote sites can perform actual hardware experiments in parallel. It realized a remote multi-user time-sharing hardware experiment system. It has achieved seamless remotes and actual hardware laboratories, which resolve conflicts among users, when many users request the same services at the same time. The top-down design support system guides students to complete projects. The course material database is organized in the form of a design-module-cell hierarchy tree, where each design-module-cell contains a sample circuit design, described in VerilogHDL. The use of XNIL wrapped VerilogHDL descriptions and specially extended XNIL vocabularies contributed to share designed modules among students and teachers as well across the Internet via the Web. The prototype of the distance learning system, integrating both the digital circuit design support system using top-down approach and the multi-user remote laboratory system for running experiment of digital circuit, has been developed. It has achieved an effective and efficient distance learning system.

This paper primarily focuses on Gate Diffusion Input (GDI) technique used for the implementation of digital logic circuits. It also discusses in detail the limitations and modifications of the basic GDI technique. Initially, GDI was a new technique used for low power digital combinational circuit design. This approach provides a reduction in power consumption, propagation delay, and area of digital circuits while the logic design complexity is small. GDI methodology allows implementation of a wide range of complex logic functions using only two transistors. GDI is a new technique for digital circuits implementation with a lot of advantages over existing ones. This paper also analyzes the recent applications of GDI technique which are the implementation of MASH 1-1 and MOD 2 modulator for Sigma Delta DACs and development of full adders for efficient arithmetic operations.

We describe our experience introducing DSP concepts via an FPGA-based advanced digital design course. The students had previously taken an introductory digital design course and a continuous-time linear systems course; a few were taking an introductory DSP course concurrently. Through a series of weekly lab exercises, the students learned advanced FPGA design methods while progressively constructing a SSB receiver for the 40-meter amateur radio band. The lab exercises introduced modulation, IQ signal representation, sampling, downconversion, frequency synthesis, CIC and FIR filters, and Hilbert transforms. The first offering of this course in Spring 2009 was successful and a repeat offering is planned for Spring 2011.

Incorporating VHDL programming and implementation using programmable logic devices (PLD) in fundamental digital design course for Electronics Engineering at undergraduate level has become increasingly essential. However it is experienced that integration of VHDL with fundamentals of digital design in one course students give lesser time and importance for VHDL programming. Hence learning objective related to VHDL programming is not achieved up to the expected level. Experience of giving additional training to interested students had shown improvement in students' performance. This paper discusses effect of designing of a separate compulsory laboratory course in VHDL and its effect on the understanding of students and achieving the learning objectives. It also discusses the effect on performance of students in Digital Design course after separating VHDL programming from it. The feedback of students shows that students learn better in laboratory course and they are motivated to learn further in the same area.

The low carrier mobility of (printed) semiconductors and high variations of the printed/flexible electronic elements are some of the most difficult challenges for the practical realization of complex printed/flexible electronic circuits. Although contemporary circuit designs accommodate some degree of process variations in conventional silicon processes largely by negative feedback, negative feedback is largely inapplicable in printed/flexible electronics. This is because the gain of the transistors is too low in electronic circuits to realize high open-loop gain, but also because negative feedback is inapplicable to digital circuits in the traditional sense. In this paper, we describe the co-design between the first three supply chains of Printed/Flexible Electronics – the co-design between our modified semiconductor, Fully-Additive Low-Temperature All-Air Low-Variation Printed/Flexible Electronics printing process and a process-variation-tolerant digital circuit design methodology. The first two co-design supply chains pertain to a low-cost screen-printing process while the last co-design chain pertains to the Quasi-Delay-Insensitive asynchronous-logic digital design methodology (vis-a-vis synchronous-logic) that is self-timed, hence virtually tolerant to any variations. We will also delineate our measurements on digital circuit based on codesign of the aforesaid supply chains, depicting the merits of our modified semiconductor, low-variation printing process, and the ensuing functional printed digital circuit.

This article describes a brief history of the development of the CAD system for integrated circuit design in Russia. The background of the beginning of the import-independent Russian CAD for digital integrated circuit design "Obsidian" is presented. What tasks were set for the developers and which results have been achieved up to the present. The results of a large set of tests obtained by "Obsidian" to compare this system with commercial CAD tools for digital integrated circuit design are presented. Further directions of the development of CAD of digital integrated circuits have been determined for separate stages of the design route.

Electronic Design Automation (EDA) technology represents the development direction of modern electronic design technology. This paper presents the traditional digital circuit design method, carefully introduces a top-down hierarchy design method, analyzes advantages and disadvantages of traditional experimental teaching, and proposes the application of EDA experimentation in digital circuit design. It is comprised of hardware and software. Numerical Control Frequency divider is taken as a typical example to display EDA experimental applications. An EDA experimental system based on FPGA/CPLD can achieve automated design of digital circuit quickly and easily, and thus it provides a good platform for the logic design and development of medium and large-scale digital circuit.

The article presents and describes in detail the laboratory work “Digital circuit design and algebra of logic: creation of digital devices in an online simulator”, conducted for high school students at Bauman Moscow State Technical University. The introduction describes the place of the lesson in the system of interaction between organizations of secondary general and higher levels of education; based on the considered problems of education in the field of digital circuitry, the rationale for the need for this laboratory work is given. The practice-oriented nature of the considered laboratory work in informatics necessitates the use of modern modeling tools. This laboratory work uses the online environment Logic.ly, which allows you to create and explore digital devices: half-adder, adder, flip-flops, multi-plexers, decoders. The main characteristics, structure and stages of the lesson, subject content and interdisciplinary connections, target subject and meta-subject results based on a modern competency-based approach are described in detail.

Computer engineering education has a strong dependence on laboratory work. Teaching students in the lab does not always consist of teaching the required course material, but also of a vast number of tutorials on different platforms. In many cases, these tutorials take significant amount of time which could be better spent doing actual course material. For that reason, E2LP project has developed a platform to be used in multiple courses, covering majority of the computer engineering curriculum. This paper presents a first step in the curriculum - a course in digital system design with laboratory exercises which are implemented on E2LP platform. The platform not only gives students hands-on experience with design and verification of digital systems, but it also provides a bridge between hardware and software because using the same platform in future courses allows students to re-use their results from previous courses and continue building their knowledge. First impression of students is positive about the experience with the platform and their feeling of usefulness of the course for their career.

Advancements in Silicon Carbide (SiC) digital integrated circuit (IC) design have enabled the ability to design complex, dense, digital blocks. Because of the large number of transistors, these complex digital designs make the time and risk of hand-crafted digital design, which has been the norm for SiC, too costly and risky. For large scale integrated digital circuits, computer aided design (CAD) tools are necessary, specifically the use of automatic synthesis, rule-based placement and signal routing software. The tools are used in progression as a design flow and are necessary for the timely and accurate creation of high-density digital designs. Application of an automated digital design flow to high-temperature SiC processes presents new challenges, such as extraction of timing characteristics at high temperatures, specifically above 400°C, as well as managing the complexity of synthesis, optimization of cell placement, verification of timing enclosure, and identifying routing constraints. These activities all require a willingness to extend and enhance the CAD software. Presented is a high temperature SiC digital synthesis flow. This flow is fully integrated with the characterization of a standard cell library that considers the variation of voltage, temperature, and process characteristics. A digital controller for a 10,000-pixel UV focal plan array (FPA) in a SiC CMOS process was designed using this high temperature digital flow. The controller is comprised of a finite state machine (FSM), that monitors several counters, shift registers and combinational logic feedback signals. The FSM is configured to optimize the FPA for different applications and exposures. The Register-Transfer Level (RTL) design of the FSM produces between 900 and 1,000 gates, depending on the temperature-dependent time closure with a total footprint of 14mm2. Typical SiC processes present a non-monotonic clock speed over temperature. The advantage of this digital design flow is that it allows the designer to target a temperature corner for the netlist design but verify its operation over a > 400°C operating range. This flow is currently being enhanced for use with NASA's SiC JFET-R process to create a high temperature communication protocol interface.

This paper describes the development of courses in the field of digital design that use Arduino boards as their main platforms. Arduino offers an intuitive development environment and multiple hardware and software resources that allow rapid development of microcontroller-based projects. However, due to the vast amount of information available, students were losing the capability to design their own prototypes. We propose a methodology that introduces the study of microcontrollers using Arduino to develop different types of projects and proceeds to study the system architecture to gain control on the device. This methodology has been used in an undergraduate course in microcontrollers and a graduate course in advanced techniques in digital design. The students of the microcontrollers course showed improved design skills and motivation compared to the students from previous versions of the course. With respect to the advanced techniques in digital design course, the students were able to take advantage of Arduino platform to gain a deep understanding of hardware/software co-design of embedded systems.

In this paper, we have developed a design environment for a stripe-shaped PMELA process and have designed digital circuits such as a serial-to-parallel converter and a PRBS generator as examples of digital VLSI circuits. The designed circuits and standard cells are fabricated in bulk CMOS process and are verified their operations. The whole circuits are fabricated in PMELA 0.5 mum CMOS technology with 1-poly-Si 1-Metal layers on glass. The measurement results show that digital circuits using PMELA TFTs are successfully integrated on glass by using this design environment.

A digital VLSI circuit design for an adaptive resonance theory (ART) neural network architecture, called the augmented ART-1 neural network (AARTI-NN) is presented. An ‘axon-synapse-tree’ structure is used to realize the activities of the short-term memories and reset subsystem. The long-term memory traces are implemented using NMOS transmission gales. PSpice circuit simulation was carried out to verify the design of a prototype, seven-node AARTI-NN. A clock-controlled delay element is included in the simulation to illustrate the functionality of the AARTI-NN. It is shown that the AARTI-NN node selection activities simulated from the circuit designed are identical to those described by the coupled differential equations governing the AARTI-NN.