49-435: 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
98-572: 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: 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 . Digital data Digital data , in information theory and information systems ,
147-562: A gate array. What distinguishes a structured ASIC from a gate array is that in a gate array, the predefined metal layers serve to make manufacturing turnaround faster. In a structured ASIC, the use of predefined metallization is primarily to reduce cost of the mask sets as well as making the design cycle time significantly shorter. For example, in a cell-based or gate-array design the user must often design power, clock, and test structures themselves. By contrast, these are predefined in most structured ASICs and therefore can save time and expense for
196-427: A low-cost I/O solution aimed at handling the computer's graphics . Customization occurred by varying a metal interconnect mask. Gate arrays had complexities of up to a few thousand gates; this is now called mid-scale integration . Later versions became more generalized, with different base dies customized by both metal and polysilicon layers. Some base dies also include random-access memory (RAM) elements. In
245-589: A manufacturer held as a stock wafer never gives 100% circuit utilization . Often difficulties in routing the interconnect require migration onto a larger array device with a consequent increase in the piece part price. These difficulties are often a result of the layout EDA software used to develop the interconnect. Pure, logic-only gate-array design is rarely implemented by circuit designers today, having been almost entirely replaced by field-programmable devices. The most prominent of such devices are field-programmable gate arrays (FPGAs) which can be programmed by
294-476: A method of obtaining low cost prototypes. Often called shuttles, these MPWs, containing several designs, run at regular, scheduled intervals on a "cut and go" basis, usually with limited liability on the part of the manufacturer. The contract involves delivery of bare dies or the assembly and packaging of a handful of devices. The service usually involves the supply of a physical design database (i.e. masking information or pattern generation (PG) tape). The manufacturer
343-401: A much higher skill requirement on the part of the design team. For digital-only designs, however, "standard-cell" cell libraries, together with modern CAD systems, can offer considerable performance/cost benefits with low risk. Automated layout tools are quick and easy to use and also offer the possibility to "hand-tweak" or manually optimize any performance-limiting aspect of the design. This
392-418: A single word. This is useful when combinations of key presses are meaningful, and is sometimes used for passing the status of modifier keys on a keyboard (such as shift and control). But it does not scale to support more keys than the number of bits in a single byte or word. Devices with many switches (such as a computer keyboard ) usually arrange these switches in a scan matrix, with the individual switches on
441-543: A switch is pressed, released, and pressed again. This polling can be done by a specialized processor in the device to prevent burdening the main CPU . When a new symbol has been entered, the device typically sends an interrupt , in a specialized format, so that the CPU can read it. For devices with only a few switches (such as the buttons on a joystick ), the status of each can be encoded as bits (usually 0 for released and 1 for pressed) in
490-448: A third-party as sub-components of a larger ASIC. They may be provided in the form of a hardware description language (often termed a "soft macro"), or as a fully routed design that could be printed directly onto an ASIC's mask (often termed a "hard macro"). Many organizations now sell such pre-designed cores – CPUs, Ethernet, USB or telephone interfaces – and larger organizations may have an entire department or division to produce cores for
539-496: Is a manufacturing method in which diffused layers, each consisting of transistors and other active devices , are predefined and electronics wafers containing such devices are "held in stock" or unconnected prior to the metallization stage of the fabrication process . The physical design process defines the interconnections of these layers for the final device. For most ASIC manufacturers, this consists of between two and nine metal layers with each layer running perpendicular to
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#1732845231587588-573: Is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-efficiency video codec . Application-specific standard product chips are intermediate between ASICs and industry standard integrated circuits like the 7400 series or the 4000 series . ASIC chips are typically fabricated using metal–oxide–semiconductor (MOS) technology, as MOS integrated circuit chips. As feature sizes have shrunk and chip design tools improved over
637-527: Is designed by using basic logic gates, circuits or layout specially for a design. Structured ASIC design (also referred to as " platform ASIC design ") is a relatively new trend in the semiconductor industry, resulting in some variation in its definition. However, the basic premise of a structured ASIC is that both manufacturing cycle time and design cycle time are reduced compared to cell-based ASIC, by virtue of there being pre-defined metal layers (thus reducing manufacturing time) and pre-characterization of what
686-526: Is information represented as a string of discrete symbols, each of which can take on one of only a finite number of values from some alphabet , such as letters or digits. An example is a text document , which consists of a string of alphanumeric characters . The most common form of digital data in modern information systems is binary data , which is represented by a string of binary digits (bits) each of which can have one of two values, either 0 or 1. Digital data can be contrasted with analog data , which
735-444: Is intermediate between § Gate-array and semi-custom design and § Full-custom design in terms of its non-recurring engineering and recurring component costs as well as performance and speed of development (including time to market ). By the late 1990s, logic synthesis tools became available. Such tools could compile HDL descriptions into a gate-level netlist . Standard-cell integrated circuits (ICs) are designed in
784-468: Is largely because ASIC devices are capable of integrating large blocks of system functionality, and systems on a chip (SoCs) require glue logic , communications subsystems (such as networks on chip ), peripherals , and other components rather than only functional units and basic interconnection. In their frequent usages in the field, the terms "gate array" and "semi-custom" are synonymous when referring to ASICs. Process engineers more commonly use
833-468: Is often referred to as a "silicon foundry" due to the low involvement it has in the process. An application-specific standard product or ASSP is an integrated circuit that implements a specific function that appeals to a wide market. As opposed to ASICs that combine a collection of functions and are designed by or for one customer , ASSPs are available as off-the-shelf components. ASSPs are used in all industries, from automotive to communications. As
882-495: Is on the silicon (thus reducing design cycle time). Definition from Foundations of Embedded Systems states that: In a "structured ASIC" design, the logic mask-layers of a device are predefined by the ASIC vendor (or in some cases by a third party). Design differentiation and customization is achieved by creating custom metal layers that create custom connections between predefined lower-layer logic elements. "Structured ASIC" technology
931-436: Is rather simpler than conversion of continuous or analog information to digital. Instead of sampling and quantization as in analog-to-digital conversion , such techniques as polling and encoding are used. A symbol input device usually consists of a group of switches that are polled at regular intervals to see which switches are switched. Data will be lost if, within a single polling interval, two switches are pressed, or
980-577: Is represented by a value from a continuous range of real numbers . Analog data is transmitted by an analog signal , which not only takes on continuous values but can vary continuously with time, a continuous real-valued function of time. An example is the air pressure variation in a sound wave . The word digital comes from the same source as the words digit and digitus (the Latin word for finger ), as fingers are often used for counting. Mathematician George Stibitz of Bell Telephone Laboratories used
1029-399: Is seen as bridging the gap between field-programmable gate arrays and "standard-cell" ASIC designs. Because only a small number of chip layers must be custom-produced, "structured ASIC" designs have much smaller non-recurring expenditures (NRE) than "standard-cell" or "full-custom" chips, which require that a full mask set be produced for every design. This is effectively the same definition as
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#17328452315871078-408: Is that standard-cell design uses the manufacturer's cell libraries that have been used in potentially hundreds of other design implementations and therefore are of much lower risk than a full custom design. Standard cells produce a design density that is cost-effective, and they can also integrate IP cores and static random-access memory (SRAM) effectively, unlike gate arrays. Gate array design
1127-430: The open-source software movement in hardware design. Soft macros are often process-independent (i.e. they can be fabricated on a wide range of manufacturing processes and different manufacturers). Hard macros are process-limited and usually further design effort must be invested to migrate (port) to a different process or manufacturer. Some manufacturers and IC design houses offer multi-project wafer service (MPW) as
1176-540: 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". 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
1225-469: The Micromatrix family of bipolar diode–transistor logic (DTL) and transistor–transistor logic (TTL) arrays. Complementary metal–oxide–semiconductor (CMOS) technology opened the door to the broad commercialization of gate arrays. The first CMOS gate arrays were developed by Robert Lipp, in 1974 for International Microcircuits, Inc. (IMI). Metal–oxide–semiconductor (MOS) standard-cell technology
1274-408: The ability to integrate analog components and other pre-designed —and thus fully verified—components, such as microprocessor cores, that form a system on a chip . The disadvantages of full-custom design can include increased manufacturing and design time, increased non-recurring engineering costs, more complexity in the computer-aided design (CAD) and electronic design automation systems, and
1323-808: 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 library will consist of design elements from central processing units , memory controllers , peripherals , motherboards , and other components. Emerging semiconductor manufacturers could use
1372-559: The design to be brought into manufacturing more quickly. Cell libraries of logical primitives are usually provided by the device manufacturer as part of the service. Although they will incur no additional cost, their release will be covered by the terms of a non-disclosure agreement (NDA) and they will be regarded as intellectual property by the manufacturer. Usually, their physical design will be pre-defined so they could be termed "hard macros". What most engineers understand as " intellectual property " are IP cores , designs purchased from
1421-410: The designer compared to gate-array based designs. Likewise, the design tools used for structured ASIC can be substantially lower cost and easier (faster) to use than cell-based tools, because they do not have to perform all the functions that cell-based tools do. In some cases, the structured ASIC vendor requires customized tools for their device (e.g., custom physical synthesis) be used, also allowing for
1470-402: 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
1519-535: The entire lifecycle from 'birth' to the destruction of the data. All digital information possesses common properties that distinguish it from analog data with respect to communications: Even though digital signals are generally associated with the binary electronic digital systems used in modern electronics and computing, digital systems are actually ancient, and need not be binary or electronic. Application-specific integrated circuit An application-specific integrated circuit ( ASIC / ˈ eɪ s ɪ k / )
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1568-476: The following conceptual stages referred to as electronics design flow , although these stages overlap significantly in practice: These steps, implemented with a level of skill common in the industry, almost always produce a final device that correctly implements the original design, unless flaws are later introduced by the physical fabrication process. The design steps also called design flow , are also common to standard product design. The significant difference
1617-519: The functionality of ASICs. Field-programmable gate arrays (FPGA) are the modern-day technology improvement on breadboards , meaning that they are not made to be application-specific as opposed to ASICs. Programmable logic blocks and programmable interconnects allow the same FPGA to be used in many different applications. For smaller designs or lower production volumes, FPGAs may be more cost-effective than an ASIC design, even in production. The non-recurring engineering (NRE) cost of an ASIC can run into
1666-520: The implementation of their designs. A solution to this problem, which also yielded a much higher density device, was the implementation of standard cells . Every ASIC manufacturer could create functional blocks with known electrical characteristics, such as propagation delay , capacitance and inductance, that could also be represented in third-party tools. Standard-cell design is the utilization of these functional blocks to achieve very high gate density and good electrical performance. Standard-cell design
1715-411: 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
1764-408: The intersections of x and y lines. When a switch is pressed, it connects the corresponding x and y lines together. Polling (often called scanning in this case) is done by activating each x line in sequence and detecting which y lines then have a signal , thus which keys are pressed. When the keyboard processor detects that a key has changed state, it sends a signal to the CPU indicating the scan code of
1813-406: The key and its new state. The symbol is then encoded or converted into a number based on the status of modifier keys and the desired character encoding . A custom encoding can be used for a specific application with no loss of data. However, using a standard encoding such as ASCII is problematic if a symbol such as 'ß' needs to be converted but is not in the standard. It is estimated that in
1862-423: The mid-1980s, a designer would choose an ASIC manufacturer and implement their design using the design tools available from the manufacturer. While third-party design tools were available, there was not an effective link from the third-party design tools to the layout and actual semiconductor process performance characteristics of the various ASIC manufacturers. Most designers used factory-specific tools to complete
1911-413: The millions of dollars. Therefore, device manufacturers typically prefer FPGAs for prototyping and devices with low production volume and ASICs for very large production volumes where NRE costs can be amortized across many devices. Early ASICs used gate array technology. By 1967, Ferranti and Interdesign were manufacturing early bipolar gate arrays. In 1967, Fairchild Semiconductor introduced
1960-404: The one below it. Non-recurring engineering costs are much lower than full custom designs, as photolithographic masks are required only for the metal layers. Production cycles are much shorter, as metallization is a comparatively quick process; thereby accelerating time to market . Gate-array ASICs are always a compromise between rapid design and performance as mapping a given design onto what
2009-480: 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 website as the basis for all future development, independent of commercial control. In the absence of a widely accepted open source hardware license,
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2058-549: The rest of the organization. The company ARM only sells IP cores, making it a fabless manufacturer . Indeed, the wide range of functions now available in structured ASIC design is a result of the phenomenal improvement in electronics in the late 1990s and early 2000s; as a core takes a lot of time and investment to create, its re-use and further development cuts product cycle times dramatically and creates better products. Additionally, open-source hardware organizations such as OpenCores are collecting free IP cores, paralleling
2107-414: The term "semi-custom", while "gate-array" is more commonly used by logic (or gate-level) designers. By contrast, full-custom ASIC design defines all the photolithographic layers of the device. Full-custom design is used for both ASIC design and for standard product design. The benefits of full-custom design include reduced area (and therefore recurring component cost), performance improvements, and also
2156-418: The user and thus offer minimal tooling charges, non-recurring engineering, only marginally increased piece part cost, and comparable performance. Today, gate arrays are evolving into structured ASICs that consist of a large IP core like a CPU , digital signal processor units, peripherals , standard interfaces , integrated memories , SRAM , and a block of reconfigurable , uncommitted logic. This shift
2205-435: The word digital in reference to the fast electric pulses emitted by a device designed to aim and fire anti-aircraft guns in 1942. The term is most commonly used in computing and electronics , especially where real-world information is converted to binary numeric form as in digital audio and digital photography . Since symbols (for example, alphanumeric characters ) are not continuous, representing symbols digitally
2254-470: The year 1986, less than 1% of the world's technological capacity to store information was digital and in 2007 it was already 94%. The year 2002 is assumed to be the year when humankind was able to store more information in digital than in analog format (the "beginning of the digital age "). Digital data come in these three states: data at rest , data in transit , and data in use . The confidentiality, integrity, and availability have to be managed during
2303-460: The years, the maximum complexity (and hence functionality) possible in an ASIC has grown from 5,000 logic gates to over 100 million. Modern ASICs often include entire microprocessors , memory blocks including ROM , RAM , EEPROM , flash memory and other large building blocks. Such an ASIC is often termed a SoC ( system-on-chip ). Designers of digital ASICs often use a hardware description language (HDL), such as Verilog or VHDL , to describe
2352-448: Was introduced by Fairchild and Motorola , under the trade names Micromosaic and Polycell, in the 1970s. This technology was later successfully commercialized by VLSI Technology (founded 1979) and LSI Logic (1981). A successful commercial application of gate array circuitry was found in the low-end 8-bit ZX81 and ZX Spectrum personal computers , introduced in 1981 and 1982. These were used by Sinclair Research (UK) essentially as
2401-475: 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
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