science

OpenCores

OpenCores is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand OpenCores rather than just read about it. In short: OpenCores is a community developing digital open-source hardware through electronic design automation (EDA), with a similar ethos to the free software movement. OpenCores hopes to eliminate redundant design work and significantly reduce development costs.

Key takeaways

OpenCores belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect OpenCores to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of OpenCores from memory before moving on to harder problems.

Reference excerpt

OpenCores is a community developing digital open-source hardware through electronic design automation (EDA), with a similar ethos to the free software movement. OpenCores hopes to eliminate redundant design work and significantly reduce development costs. A number of companies have been reported as adopting OpenCores IP in chips, or as adjuncts to EDA tools. OpenCores is also sometimes cited as an example of open source in the electronics hardware community. OpenCores has always been a commercially owned organization. In 2015, its core active users established the independent Free and Open Source Silicon Foundation (FOSSi Foundation), and created another directory on the librecores.org website as the basis for all future development, independent of commercial control. It has been shut down to redirect to a post on the FOSSi Foundation website seven years later in favor of a simple web search, reasoning that "free and open source silicon is no longer a dream".

History Damjan Lampret, one of the founders of OpenCores, stated on his website that it began in 1999. The new website and its objectives were reported publicly by EE Times in 2000 and CNET News in 2001. Through the following years it was supported by advertising and sponsorship, including by Flextronics. In mid-2007 an appeal was put out for a new backer. That November, Swedish design house ORSoC AB agreed to take over maintenance of the OpenCores website. EE Times reported in late 2008 that OpenCores had passed the 20,000 subscriber mark. In October 2010 it reached 95,000 registered users and had approximately 800 projects. In July 2012 it reached 150,000 registered users. During 2015, ORSoC AB formed a joint venture with KNCMiner AB to develop bitcoin mining machines. As this became the primary focus of the business, they were able to spend less time with the opencores.org project. In response to the growing lack of commitment, the core OpenRISC development team set up the Free and Open Source Silicon Foundation (FOSSi), and registered the librecores.org Archived 22 August 2019 at the Wayback Machine website as the basis for all future development, independent of commercial control.

Licensing In the absence of a widely accepted open source hardware license, the components produced by the OpenCores initiative use several different software licenses. The most common is the GNU LGPL, which states that any modifications to a component must be shared with the community, while one can still use it together with proprietary components. The less restrictive 3-clause BSD license is also used in some hardware projects, while the GNU GPL is often used for software components, such as models and firmware.

The OpenCores library The library will consist of design elements from central processing units, memory controllers, peripherals, motherboards, and other components. Emerging semiconductor manufacturers could use the information and license designs for free. The emphasis is on digital modules called "cores", commonly known as IP Cores. The components are used for creating both custom integrated circuits (ASICs) and FPGAs. The cores are implemented in the hardware description languages Verilog, VHDL or SystemC, which may be synthesized to either silicon or gate arrays. The project aims at using a common non-proprietary system bus named Wishbone, and most components are nowadays adapted to this bus. Among the components created by OpenCores contributors are:

OpenRISC – a highly configurable RISC central processing unit Amber (processor core) – an ARM-compatible RISC central processing unit A Zilog Z80 clone USB 2.0 controller Tri Ethernet controller, 10/100/1000 Mbit Encryption units, for example DES, AES and RSA HyperTransport Tunnel A PIC16F84 core Zet – an x86 compatible core

OpenRISC ASIC In April 2011 OpenCores opened donations for a new project to develop a complete system on a chip design based on the OpenRISC processor and implement it into an ASIC-component. OpenCores affiliated with OpenCores, for example OpenSPARC and LEON.

See also Free and Open Source Silicon Foundation Free content Open content Open-source hardware Wishbone

References

External links Official website Greenbaum, Eli (2011). "Open Source Semiconductor Core Licensing" (PDF). Harvard Journal of Law & Technology. 25 (1). Harvard: 131–157.

Illustrations

Worked examples

Example 1 — a first encounter with OpenCores

Start with the simplest possible case. Write down what OpenCores claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to OpenCores before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about OpenCores ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of OpenCores

In research: OpenCores appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses OpenCores in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: OpenCores is common in secondary-school and first-year university syllabi. It links to neighbouring topics Electronic design, Open hardware electronic devices, Open hardware organizations and companies, so understanding it makes those chapters shorter.
In everyday life: Look for OpenCores outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study OpenCores in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what OpenCores means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain OpenCores out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is OpenCores in simple terms?

Why does OpenCores matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study OpenCores?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on OpenCores.