"Digital logic" is an important professional basic course for network engineering students. The course content includes two parts: combinational logic circuit and sequential logic circuit. It takes the rapidly developing digital integrated circuits as a link, and aims to enable students to understand and master the complete knowledge required for the entire process from the requirements of the digital system to the realization of the required logic functions with integrated circuits, requiring students to be able to systematically Master the analysis, design and application of logic circuits, and establish the concept of the system, laying a good foundation for the subsequent courses of computer composition principles, computer interface and communication, and hardware analysis and design of other digital systems.
With the rapid development of large-scale integrated circuit technology, new devices, new components, new concepts and new analysis methods are constantly emerging, and the teaching of "Digital Logic" is facing new challenges. This paper introduces EDA technology, that is, electronic design automation technology, into the teaching of "Digital Logic" course, and discusses the application of EDA technology in this course.
1. Overview of EDA Technology
EDA (Electronic Design AutomaTIon electronic system design automation) technology was developed from the concepts of computer-aided design (CAD) and computer-aided engineering (CAE) in the early 1990s. It uses large-scale programmable logic devices as the design carrier. Using hardware description language as the main expression of system design, using computer, large-scale programmable logic device development software and experimental development system as design tools, through relevant development software, automatically complete the design of electronic systems from software to hardware systems a new technology. It can realize logic editing, logic simplification, logic segmentation, logic synthesis and optimization, logic layout and routing, and logic simulation. Completing the adaptation compilation, logic mapping, programming download and other work for a specific target chip, and finally forming an integrated electronic system or a dedicated integrated chip. The application of EDA technology can greatly reduce the workload and difficulty of electronic system design and reduce costs. At the same time, the use of programmable logic devices can greatly reduce the number of system chips, reduce system size, and improve system reliability. EDA technology has become an electronic system. advanced means of design.
2. The necessity of introducing EDA technology into "Digital Logic" course
1. The introduction of EDA technology in the "Digital Logic" course is the need for the development of the course itself
The main purpose of the "Digital Logic" curriculum is to enable students to master the basic knowledge and theory of digital system analysis and design, to be familiar with various logic devices of different scales, and to master the basic methods of analysis and design of various logic circuits. Lay a solid foundation for hardware analysis and design of digital systems. For many years, we still follow the traditional course mode, and the teaching content of the "Digital Logic" course still pays more attention to the theoretical and systematic nature of the teaching content. However, it is still accustomed to use circuit diagrams to describe the connection relationship of the system, and stays on the traditional design method, which is not suitable for the realization of complex and large-scale digital systems.
With the emergence of programmable logic devices and EDA technology, the realization of digital system functions and system design methods have undergone revolutionary changes. Therefore, the traditional teaching content has been reformed and integrated, and EDA technology has been introduced into the "Digital Logic" course. It is very necessary in teaching.
2. The introduction of EDA technology in the "Digital Logic" course is the need to cultivate students' independent innovation ability
Accelerating the improvement of independent innovation ability is an important task and a long-term task during the "Eleventh Five-Year Plan" period in my country. To this end, we must speed up the construction of a technological innovation system, and cultivating students' innovative ability is an important part of it.
At present, with the continuous improvement of the cost performance of programmable logic devices and the continuous improvement of software development functions, in the design of electronic systems involving communication, national defense, aerospace, medicine, industrial automation, instrumentation and computer applications, the content of EDA technology It is rising sharply, and various industries have increasingly urgent needs for the development of their own ASICs. Based on this technology, they can rely on their own strength to develop products with independent intellectual property rights, and engineering students are the main body of future technological innovation. Therefore, it is very necessary to introduce EDA technology into the "Digital Logic" course, to cultivate students' ability to adapt to modern digital system design, to broaden students' horizons, to cultivate students' innovative awareness and ability, and to lay a good foundation for their future employment or entrepreneurship. Base.
3. The method of applying EDA technology to the "Digital Logic" course
To apply EDA technology to the teaching of "Digital Logic" course, and to combine EDA technology and "Digital Logic" course organically, it is necessary to study and explore some effective methods.
1. Well-arranged and organized teaching
EDA technology is an application technology. It should follow the principle of theoretical teaching supplemented by computer practice. The teaching content should focus on the principle of programmable devices, hardware design description language, EDA design tool software, and digital system design methods. The system introduces EDA technology. Specific practices include:
First, add 10 to 15 hours for EDA teaching and computer practice. By introducing the structure and principle of programmable devices and the grammar rules of VHDL language, students are gradually familiar with an EDA tool (such as Max Plus II software) with examples. To enable students to have a more comprehensive understanding of the design process and methods of electronic systems.
Second, add 4 hours of EDA technology-based experiments on the basis of traditional experiments, and arrange some verification and simple design experiments, so that students can master the principles and methods of EDA technology in a relatively short period of time, and further familiarize themselves with the basic principles and methods of EDA technology. The whole process of designing digital systems with EDA technology has the ability to initially design and develop digital systems.
Third, arrange the course design link. In this link, design and comprehensive topics are arranged. Students are required to start from analyzing the requirements of the topic and propose a plan, and determine the plan through discussion. Based on the Max ten plus II software, the schematic diagram can be used to design input, Text editing and input, waveform input, and mixed input are used to complete all editing, compiling, logic analysis, device assembly, and functional timing simulation. Through this link, students have a relatively complete ability to design and develop digital systems, which lays the foundation for their continued study and related work in the future.
2. Actively try to use EDA for classroom teaching
For students, the difficulties in learning "Digital Logic" are: first, some content is abstract and difficult to understand; second, they are at a loss for some complex changes in digital circuits; third, circuit design problems. Therefore, in the classroom teaching of "digital logic", we can try to apply EDA to solve these problems. With the powerful simulation and timing simulation functions of EDA software, the incomprehensible phenomena and complex change processes in the course can be displayed in the form of graphics, tables and curves, so that students can intuitively see the change process of each step of the circuit. Deep understanding of the nature of digital circuits. With the help of the powerful troubleshooting function of the EDA software, the circuit modification can be easily carried out, which solves this difficult problem in the "Digital Logic" course. These methods play an active role in improving teaching efficiency, expanding course content, improving classroom teaching effect, and stimulating and mobilizing students' initiative and creativity in learning.
3. Strengthen the construction of EDA laboratory
Strengthening the construction of EDA laboratory and improving the experimental environment should start from both hardware and software. In terms of software, there are currently many EDA software, which have certain differences in simulation performance and price, and can be roughly divided into circuit simulation software, circuit board-level design software, programmable logic device development software and chip-level design software. They play a role in various design stages of a digital system, respectively. The software tools mainly equipped with the student version are: circuit and system simulation analysis tools such as Pspie; digital circuit simulation tools such as EWB (Electronic Workbench), which is a set of computer-aided analysis software for electronic circuits based on a PC platform. Its integrated environment includes Principle design, system simulation, digital/analog hybrid simulation and virtual instrument, etc., constitute an electronic simulation work platform on the computer. The simulation results can be displayed on the virtual measuring instrument, and the circuit design can be modified and simulated at the same time. The operation is simple and convenient. The digital programmable chip design tool adopts Max plus Ⅱ of Altera Corporation of the United States, and the general design EDA tool adopts Protel99, which has circuit diagram input, PCB automatic layout and gridless routing, mixed circuit simulation and column. design, etc. In terms of hardware, an EDA experimental computer room is built and an experimental simulation box is purchased. After completing the software compilation and simulation on the computer, students can download the program to the hardware system to complete the design of the digital system.
According to the above method, we have practiced in the digital logic course of our college's network engineering major (network and informationization direction). Teaching practice shows that students have the ability to design and simulate digital systems with the help of Max plus II software after listening to lectures and computer training. The application of EDA technology in the "Digital Logic" course effectively promotes the reform of the "Digital Logic" course, updates the content of the "Digital Logic" course, and provides a platform for students to apply modern technology, so that students can be proficient in The use of EDA software provides a good guarantee for its future development.
Responsible editor: tzh