EDA Tools: Simulink & Electric
Electronic design automation (EDA), also referred to as electronic computer-aided design (ECAD), is a category of software tools for designing electronic systems such as integrated circuits and printed circuit boards. The tools work together in a design flow that chip designers use to design and analyze entire semiconductor chips. Since a modern semiconductor chip can have billions of components, EDA tools are essential for their design.
1. Simulink
Simulink® is a MATLAB-based graphical programming environment for modelling, simulating and analyzing multidomain dynamical systems. Its primary interface is a graphical block diagramming tool and a customizable set of block libraries.
Simulink® is a block diagram environment for multidomain simulation and Model-Based Design. It supports system-level design, simulation, automatic code generation, and continuous test and verification of embedded systems. Simulink provides a graphical editor, customizable block libraries, and solvers for modelling and simulating dynamic systems. It is integrated with MATLAB®, enabling you to incorporate MATLAB algorithms into models and export simulation results to MATLAB for further analysis.
Simulink handles data in three categories:
- Signals — Block inputs and outputs, computed during the simulation.
- States — Internal values, representing the dynamics of the block, computed during the simulation.
- Parameters — Values that affect the behaviour of a block, controlled by the user.
At each time step, Simulink computes new values for signals and states. By contrast, you specify parameters when you build the model and can occasionally change them while a simulation is running.
Model-Based Design with Simulink :
Modelling is a way to create a virtual representation of a real-world system. You can simulate this virtual representation under a wide range of conditions to see how it behaves. Modelling and simulation are valuable for testing conditions that are difficult to reproduce with hardware prototypes alone. This is especially true in the early phase of the design process when the hardware is not yet available. Iterating between modelling and simulation can improve the quality of the system design early, by reducing the number of errors found later in the design process.
You can automatically generate code from a model and, when software and hardware implementation requirements are included, create test benches for system verification. Code generation saves time and prevents the introduction of manually coded errors.
In Model-Based Design, a system model is at the centre of the workflow. Model-Based Design enables fast and cost-effective development of dynamic systems, including control systems, signal processing systems, and communications systems.
Model-Based Design allows you to:
- Use a common design environment across project teams
- Link designs directly to requirements
- Identify and correct errors continuously by integrating testing with design
- Refine algorithms through multidomain simulation
- Automatically generate embedded software code and documentation
- Develop and reuse test suite
Applications :
Explore examples that illustrate the modelling and simulation of dynamic systems for specific industries and applications provided by Matlab®
- General Applications
Example models illustrating general applications - Automotive Applications
Model and simulate automotive systems using Simulink® and other MathWorks® products - Aerospace Applications
Model aerospace systems using Simulink and Aerospace Blockset™ software - Industrial Automation Applications
Example models illustrating industrial automation applications - Signal Processing
Model signal processing and communications systems using DSP System Toolbox™ software - Physical Modeling
Model physical systems using Simscape™software - Complex Logic
Model complex logic using Stateflow® diagrams - Discrete-Event Simulation
Model and simulate discrete-event systems - Systems Engineering
Design and analyze system architecture using System Composer™ software - Large-Scale Modeling
Model architecture for large models and multi-user development teams
2. Electric
If you are looking for open-source electronic design automation (EDA) software, Electric is one of the highly efficient options. This very-large-scale-integration (VLSI) tool lets you draw schematics and create integrated circuit (IC) layouts digitally. Electric 9.07 is also compatible with hardware description languages like VHDL and Verilog.
The different design technologies :
The default library of Electric software consists of most of the components necessary for IC design, supporting different technologies and multiple file formats. The different categories of circuits that Electric can design include a complementary metal-oxide-semiconductor (CMOS), n-channel MOSFETs, bipolar technologies based on integrated injector logics, newer layout technologies like thin-film, carbon nanotube and photonics, abstract circuits like digital filters, temporal logics and so on. Each design technology comes out on the interface as a collection of components connected with wires.
A major advantage of the software is that the technology describes the technical parameters of the components and wires, like design rules, simulation aspects and graphical descriptions to name a few. Users can also add modules to custom-design the environment with the help of a technology editor.
Analysis and synthesis properties :
Electric has a strong inventory of analysis and synthesis tools that create the simulation by storing the connectivity and geometry. These include:
- Design-rule checking: This tool checks and validates the layout’s design rules compliance and displays spacing errors, notch errors, minimum size errors and other violations. Interfaces like Caliber and Assura can be used to check the design rules of external circuits.
- Electrical rule checking: The electric rule checker has two functionalities: ensure proper electrical contact and spacing throughout the circuit, and check for antenna rule violations.
- Simulation: Electric has an integrated 12-state switch-level simulator called ALS and a built-in IRSIM simulator version that displays waveforms in a separate window and allows users to cross-probe. Electric also supports several simulators which have to be attained exclusively, for example, device-level simulators like Spice, switch-level simulators like Silos, Tegas, ESIM, RSIM, RNL, Cosmos and Mossim, and behavioural simulators like Verilog and Fast-Henry.
- Generation: Electric has four inbuilt generator technologies: PLA generator, which functions from a library of PLA elements, facilitating customised arrays, ROM generator, which builds a ROM layout from a personality table, Pad frame generator, which places pad cells around a chip core and wires them together, Fill generator, which ensures proper fills during fabrication by placing geometry on relevant layers
- Routing: Electric comes with several routing modules. The maze router helps in connecting single wires between points, while the sea-of-gates router uses multi-threading to run wires faster. Two other routers ensure wires are properly placed. Other than that, the auto-router creates exclusive connections in overlapping regions. The mimic router adds extra wires in situations similar to those when the user runs by hand. The river router connects parallel wires in a channel between cells.
- Network consistency checking: Electric adopts graph isomorphism to compare a layout with its equivalent schematic and evaluates the network consistency. It is also able to compare two different versions of a schematic or layout for network consistency checking.
- Logical Effort: Logical Effort helps in marking digital logic gates with fan-out information, ensuring optimal speed of the circuit.
- VHDL: The VHSIC Hardware Description Language (VHDL) system uses a layout to generate VHDL and compiles the program to netlists of various formats. Then, with the help of built-in simulators, these netlists can be simulated and converted into a layout with the silicon compiler or saved to memory.
- Silicon compiler: The netlist created from VHDL is fed to the silicon compiler for placing and routing standard cells.
- Compaction: The compactor tool ensures minimal spacing, or compaction, of the circuit by adjusting the geometry along X and Y axes.
