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Web applications for electronics design provide an environment where users can apply their knowledge, and thus accelerate learning. These virtual laboratories provide plenty instruments and pre-built circuits or systems, that enable users to do experiments at any time and for as long as they need to. The purpose of this article is to outline the basic features of three powerful web-based tools; EDA Playground, ElvisLab and Spicy VOLTsim. These applications require no installation and can be used by students at all levels. The users can simulate HDLs, select the desired simulator or synthesis tool, view waveforms, draw a schematic, get an instant 3D view of a circuit and much more. The main components of these valuable tools are described in the following paragraphs.
EDA Playground is a free web application that gives its users the opportunity to simulate SystemVerilog, Verilog, VHDL, C++/SystemC, Migen and other HDLs. Engineers can use EDA Playground to simulate, edit and view waveforms and share their HDL sourcecode. All you need to try this powerful tool, is a web browser. It runs on any operating system and no pre-installation is required.
This application is explicitly designed for small prototypes and examples that follow a simple methodology. To start with, you have to type in your code, select the desired simulator or synthesis tool and click run. After the simulation is executed, the produced waveforms can be demonstrated in a separate window. All code and waveform displays can be saved as a static HTML link, enabling others to open and re-run the code in order to verify the results.
This online tool supports several HDLs, runs open source and free simulation and synthesis EDA tools. An account validation is required, when using certain simulators such as Cadence Incisive. EDA Playground uses the open source Yosys and Verilog-to-Routing (VTR) flows. Engineers can experiment with several libraries and verification methodologies, such as, UVM, OVL and SVUnit. You can try out this simple Verilog UVM test bench.
EDA Playground provides the ideal environment to increase educational productivity, by simplifying the access to EDA tools and libraries. One of its key features is that code and simulation results can be shared using a web link. The latter can be used to optimize web forum discussions, and thus accelerate the rate of learning. The ultimate goal of EDA Playground is to promote and facilitate design and test bench development. It can become a valuable tool when it comes to HDL Coding Practices and quick prototyping. It can be used to support actual university courses by providing web-based labs and tutorials. Using this application, students can test their HDL coding and debug skills.
The EDA Playground web application is located at http://www.edaplayground.com/
EPWave (EDA Playground Wave) is an interactive browser-based waveviewer. The EPWave web application is located at http://www.edaplayground.com/w and the EPWave documentation is available at http://epwave.readthedocs.org
Tutorials for Verilog, SystemVerilog, UVM, and VHDL, news, features, and more, can be found on Youtube: EDA Playground on YouTube
ElvisLab is an acronym standing for Electronic Virtual Student Lab. This application includes plenty virtual instruments and pre-built circuits and systems. The use of ElvisLab is quite straightforward and doesn’t require reading of an instruction manual. The complete catalogue of experiments, some of which are not available yet, is displayed on the application homepage. The help and tips buttons allow you to get hints and some general information regarding the usage of the program.
A top down description of the Cellular phone [Retrieved from http://ims.unipv.it/~ElvisLab/ElvisLite/ElvisLite.html]
Every ElvisLab experiment has four basic ingredients: generators, displays, control and special sources and other building elements. The interactive and user friendly experiments divide the screen into multiple sections. The top left area is the console that includes buttons or numerical steppers which are used to define the input parameters. The waveforms are usually displayed in the top right area. Additional sections are included in order to describe the control panel or other features that are critical for the definition of the experiment.
ElvisLab experimental setup [Retrieved from http://ims.unipv.it/~ElvisLab/ElvisLite/ElvisLite.html]
One of the widely used displays is the oscilloscope, an instrument that plots how repetitive waveforms change in time. The program uses default axis intervals. In case the vertical amplitude isn’t between certain minimum and maximum limits, you have the ability to adjust the waveform view accordingly. You can retrieve the coordinates of a certain point of the curve by simply moving the marker.
Oscilloscope tutorial [Retrieved from http://ims.unipv.it/~ElvisLab/ElvisLite/ElvisLite.html]
This tool enables you to perform experiments like the ones that are conventionally done in real laboratories. After an introduction regarding the main features, detailed instructions on how to proceed are available at each step. ElvisLAb uses a console in order to control all the parameters that define an experiment. Access this exiting application at http://ims.unipv.it/~ElvisLab/ElvisLite/ElvisLite.html, change the parameters and observe the results to realise how the console commands work.
The understanding of electrical circuits is essential for all students pursuing electronics. The first step in understanding fundamental laws of electronics and electronic components, is to create an abstraction of circuits. This abstraction is a good approximation of a schematic diagram. The latter is the starting point for tasks, such as defining the behaviour and working principles of devices, mathematical description, and simulation. Thus, linking the abstraction with the schematic is of utmost importance for the analysis and design of electronic circuits. A valuable tool that provides detailed schematics is Spicy VOLTsim, an editor, simulator and 3D-visualizer of analog circuits.
The voltage at the gate of the transistor on the right is high enough so that that the transistor is no longer in saturation and is shown in yellow instead of green
This online learning-application uses computer graphics, in order to implement a display methodology for automated placement of devices in three-dimensional schematics. Spicy VOLTsim includes components such as circuit editor, simulation engine and animation display. With a simple drag and drop feature the user can place the devices in the graphical environment. In order to complete the schematic, drawing of the connection lines and setting of the device parameters are necessary. After the circuit is completed and the simulation time is set, the transient simulation is ready to run. An instant 3D view of the circuit is generated, according to the combined information from the simulation results and the placement data of the editor. The devices are placed correlatively to the electrical potentials of their terminals. In case the potentials change over time, an animated view of the devices is produced in accordance to the different images at various time-steps. During animation, the devices change colours dynamically in order to display their status of operation. Each step of the animation can be reached through a timeline.
Experienced users have the ability to control several functions of the analog simulation, in order to manage the simulation models and interact with the SPICE-simulator. Detailed information about the devices and circuits are available to the users via a help-browser. The example circuits of the comprehensive helpdesk can be implemented in order to verify the results included in the tutorials. Video-tutorials that introduce the functionality of the application, are also available to enable the users a fast entry into Spicy VOLTsim . The user can implement the same functions featured in the videos in order to follow the tutorials in real-time.
The Spicy VOLTsim web application is located here.