Xerox ColorQube 8570 - Main controller - Xilinx Spartan XC3S400A-0205

A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware description language (HDL), similar to that used for an application-specific integrated circuit (ASIC). Circuit diagrams were previously used to specify the configuration, but this is increasingly rare due to the advent of

electronic design automation 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 ...

tools. FPGAs contain an array of programmable logic blocks, and a hierarchy of reconfigurable interconnects allowing blocks to be wired together. Logic blocks can be configured to perform complex combinational functions, or act as simple logic gates like AND and XOR. In most FPGAs, logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory. Many FPGAs can be reprogrammed to implement different logic functions, allowing flexible

reconfigurable computing Reconfigurable computing is a computer architecture combining some of the flexibility of software with the high performance of hardware by processing with very flexible high speed computing fabrics like FPGA, field-programmable gate arrays (FPGA ...

as performed in computer software. FPGAs have a remarkable role in

embedded system An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' ...

development due to their capability to start system software development simultaneously with hardware, enable system performance simulations at a very early phase of the development, and allow various system trials and design iterations before finalizing the system architecture.

History

The FPGA industry sprouted from programmable read-only memory (PROM) and programmable logic devices (PLDs). PROMs and PLDs both had the option of being programmed in batches in a factory or in the field (field-programmable). Altera was founded in 1983 and delivered the industry's first reprogrammable logic device in 1984 – the EP300 – which featured a quartz window in the package that allowed users to shine an ultra-violet lamp on the die to erase the EPROM cells that held the device configuration.

Xilinx Xilinx, Inc. ( ) was an American technology and semiconductor company that primarily supplied programmable logic devices. The company was known for inventing the first commercially viable field-programmable gate array (FPGA) and creating the fi ...

produced the first commercially viable field-programmable gate array in 1985the XC2064. The XC2064 had programmable gates and programmable interconnects between gates, the beginnings of a new technology and market.Funding Universe.
Xilinx, Inc.
Retrieved January 15, 2009. The XC2064 had 64 configurable logic blocks (CLBs), with two three-input lookup tables (LUTs).Clive Maxfield, Programmable Logic DesignLine,
Xilinx unveil revolutionary 65nm FPGA architecture: the Virtex-5 family
. May 15, 2006. Retrieved February 5, 2009. In 1987, the Naval Surface Warfare Center funded an experiment proposed by Steve Casselman to develop a computer that would implement 600,000 reprogrammable gates. Casselman was successful and a patent related to the system was issued in 1992. Altera and Xilinx continued unchallenged and quickly grew from 1985 to the mid-1990s when competitors sprouted up, eroding a significant portion of their market share. By 1993, Actel (now Microsemi) was serving about 18 percent of the market. The 1990s were a period of rapid growth for FPGAs, both in circuit sophistication and the volume of production. In the early 1990s, FPGAs were primarily used in

telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than tha ...

s and

networking Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics ...

. By the end of the decade, FPGAs found their way into consumer, automotive, and industrial applications. By 2013, Altera (31 percent), Actel (10 percent) and Xilinx (36 percent) together represented approximately 77 percent of the FPGA market. Companies like Microsoft have started to use FPGAs to accelerate high-performance, computationally intensive systems (like the data centers that operate their

Bing search engine Microsoft Bing (commonly known as Bing) is a web search engine owned and operated by Microsoft. The service has its origins in Microsoft's previous search engines: MSN Search, Windows Live Search and later Live Search. Bing provides a variety ...

), due to the performance per watt advantage FPGAs deliver. Microsoft began using FPGAs to accelerate Bing in 2014, and in 2018 began deploying FPGAs across other data center workloads for their

Azure Azure may refer to: Colour * Azure (color), a hue of blue ** Azure (heraldry) ** Shades of azure, shades and variations Arts and media * ''Azure'' (Art Farmer and Fritz Pauer album), 1987 * Azure (Gary Peacock and Marilyn Crispell album), 2013 ...

cloud computing Cloud computing is the on-demand availability of computer system resources, especially data storage ( cloud storage) and computing power, without direct active management by the user. Large clouds often have functions distributed over m ...

platform.

Growth

The following timelines indicate progress in different aspects of FPGA design.

Gates

* 1987: 9,000 gates, Xilinx * 1992: 600,000, Naval Surface Warfare Department * Early 2000s: millions * 2013: 50 million, Xilinx

Market size

* 1985: First commercial FPGA : Xilinx XC2064 * 1987: $14 million * : >$385 million * 2005: $1.9 billionDylan McGrath, ''EE Times'',
FPGA Market to Pass $2.7 Billion by '10, In-Stat Says
. May 24, 2006. Retrieved February 5, 2009. * 2010 estimates: $2.75 billion * 2013: $5.4 billion * 2020 estimate: $9.8 billion

Design starts

A ''design start'' is a new custom design for implementation on an FPGA. * 2005: 80,000Dylan McGrath, ''EE Times'',
Gartner Dataquest Analyst Gives ASIC, FPGA Markets Clean Bill of Health
. June 13, 2005. Retrieved February 5, 2009. * 2008: 90,000

Design

Contemporary FPGAs have ample logic gates and RAM blocks to implement complex digital computations. FPGAs can be used to implement any logical function that an ASIC can perform. The ability to update the functionality after shipping, partial re-configuration of a portion of the design and the low non-recurring engineering costs relative to an ASIC design (notwithstanding the generally higher unit cost), offer advantages for many applications. As FPGA designs employ very fast I/O rates and bidirectional data buses, it becomes a challenge to verify correct timing of valid data within setup time and hold time. Floor planning helps resource allocation within FPGAs to meet these timing constraints. Some FPGAs have analog features in addition to digital functions. The most common analog feature is a programmable slew rate on each output pin, allowing the engineer to set low rates on lightly loaded pins that would otherwise ring or couple unacceptably, and to set higher rates on heavily loaded high-speed channels that would otherwise run too slowly. Also common are quartz- crystal oscillators, on-chip resistance-capacitance oscillators, and phase-locked loops with embedded voltage-controlled oscillators used for clock generation and management as well as for high-speed serializer-deserializer (SERDES) transmit clocks and receiver clock recovery. Fairly common are differential comparators on input pins designed to be connected to

differential signaling Differential signalling is a method for electrically transmitting information using two complementary signals. The technique sends the same electrical signal as a differential pair of signals, each in its own conductor. The pair of conduc ...

channels. A few "

mixed signal A mixed-signal integrated circuit is any integrated circuit that has both analog circuits and digital circuits on a single semiconductor die.analog-to-digital converters (ADCs) and

digital-to-analog converter In electronics, a digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function. There are several DAC archi ...

s (DACs) with analog signal conditioning blocks allowing them to operate as a system-on-a-chip (SoC). Such devices blur the line between an FPGA, which carries digital ones and zeros on its internal programmable interconnect fabric, and field-programmable analog array (FPAA), which carries analog values on its internal programmable interconnect fabric.

Logic blocks

The most common FPGA architecture consists of an array of logic blocks (called configurable logic blocks, CLBs, or logic array blocks, LABs, depending on vendor), I/O pads, and routing channels. Generally, all the routing channels have the same width (number of wires). Multiple I/O pads may fit into the height of one row or the width of one column in the array. "An application circuit must be mapped into an FPGA with adequate resources. While the number of CLBs/LABs and I/Os required is easily determined from the design, the number of routing tracks needed may vary considerably even among designs with the same amount of logic. (For example, a crossbar switch requires much more routing than a

systolic array In parallel computer architectures, a systolic array is a homogeneous network of tightly coupled data processing units (DPUs) called cells or nodes. Each node or DPU independently computes a partial result as a function of the data received f ...

with the same gate count. Since unused routing tracks increase the cost (and decrease the performance) of the part without providing any benefit, FPGA manufacturers try to provide just enough tracks so that most designs that will fit in terms of lookup tables (LUTs) and I/Os can be

routed Routing is the process of selecting a path for traffic in a network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone netwo ...

. This is determined by estimates such as those derived from Rent's rule or by experiments with existing designs." In general, a logic block consists of a few logical cells (called ALM, LE, slice etc.). A typical cell consists of a 4-input LUT, a full adder (FA) and a D-type flip-flop. These might be split into two 3-input LUTs. In ''normal mode'' those are combined into a 4-input LUT through the first multiplexer (mux). In ''arithmetic'' mode, their outputs are fed to the adder. The selection of mode is programmed into the second mux. The output can be either synchronous or asynchronous, depending on the programming of the third mux. In practice, entire or parts of the adder are stored as functions into the LUTs in order to save

space Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually con ...

Hard blocks

Modern FPGA families expand upon the above capabilities to include higher level functionality fixed in silicon. Having these common functions embedded in the circuit reduces the area required and gives those functions increased speed compared to building them from logical primitives. Examples of these include multipliers, generic DSP blocks, embedded processors, high-speed I/O logic and embedded memories. Higher-end FPGAs can contain high speed multi-gigabit transceivers and ''hard IP cores'' such as processor cores,

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in ...

medium access control units, PCI/ PCI Express controllers, and external memory controllers. These cores exist alongside the programmable fabric, but they are built out of

transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...

s instead of LUTs so they have ASIC-level performance and power consumption without consuming a significant amount of fabric resources, leaving more of the fabric free for the application-specific logic. The multi-gigabit transceivers also contain high performance analog input and output circuitry along with high-speed serializers and deserializers, components which cannot be built out of LUTs. Higher-level physical layer (PHY) functionality such as line coding may or may not be implemented alongside the serializers and deserializers in hard logic, depending on the FPGA.

Soft core

An alternate approach to using hard-macro processors is to make use of

soft processor A soft microprocessor (also called softcore microprocessor or a soft processor) is a microprocessor core that can be wholly implemented using logic synthesis. It can be implemented via different semiconductor devices containing programmable logi ...

IP cores that are implemented within the FPGA logic. Nios II, MicroBlaze and

Mico32 LatticeMico32 is a 32-bit microprocessor reduced instruction set computer (RISC) soft core from Lattice Semiconductor optimized for field-programmable gate arrays (FPGAs). It uses a Harvard architecture, which means the instruction and data buses a ...

are examples of popular softcore processors. Many modern FPGAs are programmed at "run time", which has led to the idea of

or reconfigurable systems – CPUs that reconfigure themselves to suit the task at hand. Additionally, new, non-FPGA architectures are beginning to emerge. Software-configurable microprocessors such as the Stretch S5000 adopt a hybrid approach by providing an array of processor cores and FPGA-like programmable cores on the same chip.

Integration

In 2012 the coarse-grained architectural approach was taken a step further by combining the logic blocks and interconnects of traditional FPGAs with embedded

microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...

s and related peripherals to form a complete " system on a programmable chip". This work mirrors the architecture created by Ron Perloff and Hanan Potash of Burroughs Advanced Systems Group in 1982 which combined a reconfigurable CPU architecture on a single chip called the SB24. Examples of such hybrid technologies can be found in the

Zynq-7000 all Programmable SoC, which includes a 1.0 GHz dual-core ARM Cortex-A9 MPCore processor embedded within the FPGA's logic fabric or in the Altera Arria V FPGA, which includes an 800 MHz dual-core ARM Cortex-A9 MPCore. The Atmel FPSLIC is another such device, which uses an AVR processor in combination with Atmel's programmable logic architecture. The Microsemi

SmartFusion SmartFusion is a family of microcontrollers with an integrated FPGA of Actel. The device includes an ARM Cortex-M3 hard processor core (with up to 512kB of flash and 64kB of RAM) and analog peripherals such as a multi-channel ADC and DACs in addi ...

devices incorporate an ARM Cortex-M3 hard processor core (with up to 512 kB of flash and 64 kB of RAM) and analog peripherals such as a multi-channel analog-to-digital converters and

s to their

flash memory Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both u ...

-based FPGA fabric.

Clocking

Most of the circuitry built inside of an FPGA is synchronous circuitry that requires a

clock signal In electronics and especially synchronous digital circuits, a clock signal (historically also known as ''logic beat'') oscillates between a high and a low state and is used like a metronome to coordinate actions of digital circuits. A clock s ...

. FPGAs contain dedicated global and regional routing networks for clock and reset so they can be delivered with minimal skew. Also, FPGAs generally contain analog phase-locked loop and/or

delay-locked loop In electronics, a delay-locked loop (DLL) is a pseudo-digital circuit similar to a phase-locked loop (PLL), with the main difference being the absence of an internal voltage-controlled oscillator, replaced by a delay line. A DLL can be used to ch ...

components to synthesize new clock frequencies as well as attenuate jitter. Complex designs can use multiple clocks with different frequency and phase relationships, each forming separate clock domains. These clock signals can be generated locally by an oscillator or they can be recovered from a high speed serial data stream. Care must be taken when building clock domain crossing circuitry to avoid metastability. FPGAs generally contain blocks of RAMs that are capable of working as dual port RAMs with different clocks, aiding in the construction of building FIFOs and dual port buffers that connect differing clock domains.

3D architectures

To shrink the size and power consumption of FPGAs, vendors such as Tabula and

have introduced 3D or stacked architectures.Lawrence Latif, The Inquirer.
FPGA manufacturer claims to beat Moore's Law
" October 27, 2010. Retrieved May 12, 2011. Following the introduction of its 28 nm 7-series FPGAs, Xilinx said that several of the highest-density parts in those FPGA product lines will be constructed using multiple dies in one package, employing technology developed for 3D construction and stacked-die assemblies. Xilinx's approach stacks several (three or four) active FPGA dies side by side on a silicon interposer – a single piece of silicon that carries passive interconnect. The multi-die construction also allows different parts of the FPGA to be created with different process technologies, as the process requirements are different between the FPGA fabric itself and the very high speed 28 Gbit/s serial transceivers. An FPGA built in this way is called a '' heterogeneous FPGA''. Altera's heterogeneous approach involves using a single monolithic FPGA die and connecting other die/technologies to the FPGA using Intel's embedded multi-die interconnect bridge (EMIB) technology.

Programming

To define the behavior of the FPGA, the user provides a design in a hardware description language (HDL) or as a schematic design. The HDL form is more suited to work with large structures because it's possible to specify high-level functional behavior rather than drawing every piece by hand. However, schematic entry can allow for easier visualization of a design and its component modules. Using an

tool, a technology-mapped netlist is generated. The netlist can then be fit to the actual FPGA architecture using a process called place-and-route, usually performed by the FPGA company's proprietary place-and-route software. The user will validate the map, place and route results via timing analysis,

simulation A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the ...

, and other verification and validation methodologies. Once the design and validation process is complete, the binary file generated, typically using the FPGA vendor's proprietary software, is used to (re-)configure the FPGA. This file is transferred to the FPGA/CPLD via a serial interface ( JTAG) or to an external memory device like an EEPROM. The most common HDLs are VHDL and Verilog as well as extensions such as SystemVerilog. However, in an attempt to reduce the complexity of designing in HDLs, which have been compared to the equivalent of assembly languages, there are moves to raise the abstraction level through the introduction of alternative languages. National Instruments' LabVIEW graphical programming language (sometimes referred to as "G") has an FPGA add-in module available to target and program FPGA hardware. Verilog was created to simplify the process making HDL more robust and flexible. Verilog is currently the most popular. Verilog creates a level of abstraction to hide away the details of its implementation. Verilog has a C-like syntax, unlike VHDL. To simplify the design of complex systems in FPGAs, there exist libraries of predefined complex functions and circuits that have been tested and optimized to speed up the design process. These predefined circuits are commonly called '' intellectual property (IP) cores'', and are available from FPGA vendors and third-party IP suppliers. They are rarely free, and typically released under proprietary licenses. Other predefined circuits are available from developer communities such as OpenCores (typically released under free and open source licenses such as the GPL, BSD or similar license), and other sources. Such designs are known as " open-source hardware." In a typical design flow, an FPGA application developer will simulate the design at multiple stages throughout the design process. Initially the RTL description in VHDL or Verilog is simulated by creating test benches to simulate the system and observe results. Then, after the synthesis engine has mapped the design to a netlist, the netlist is translated to a gate-level description where simulation is repeated to confirm the synthesis proceeded without errors. Finally the design is laid out in the FPGA at which point propagation delays can be added and the simulation run again with these values back-annotated onto the netlist. More recently, OpenCL (Open Computing Language) is being used by programmers to take advantage of the performance and power efficiencies that FPGAs provide. OpenCL allows programmers to develop code in the C programming language and target FPGA functions as OpenCL kernels using OpenCL constructs. For further information, see high-level synthesis and C to HDL. Most FPGAs rely on an SRAM-based approach to be programmed. These FPGAs are in-system programmable and re-programmable, but require external boot devices. For example,

or EEPROM devices may often load contents into internal SRAM that controls routing and logic. The SRAM approach is based on CMOS. Rarer alternatives to the SRAM approach include: * Fuse: one-time programmable. Bipolar. Obsolete. * Antifuse: one-time programmable. CMOS. Examples: Actel SX and Axcelerator families; Quicklogic Eclipse II family. * PROM: programmable read-only memory technology. One-time programmable because of plastic packaging. Obsolete. * EPROM: erasable programmable read-only memory technology. One-time programmable but with window, can be erased with ultraviolet (UV) light. CMOS. Obsolete. * EEPROM: electrically erasable programmable read-only memory technology. Can be erased, even in plastic packages. Some but not all EEPROM devices can be in-system programmed. CMOS. * Flash: flash-erase EPROM technology. Can be erased, even in plastic packages. Some but not all flash devices can be in-system programmed. Usually, a flash cell is smaller than an equivalent EEPROM cell and is therefore less expensive to manufacture. CMOS. Example: Actel ProASIC family.

Manufacturers

In 2016, long-time industry rivals

(now part of AMD) and Altera (now an Intel subsidiary) were the FPGA market leaders. At that time, they controlled nearly 90 percent of the market. Both Xilinx (now AMD) and Altera (now Intel) provide proprietary

software for

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...

and

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which i ...

( ISE/ Vivado and

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) which enables engineers to

design A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process or the result of that plan or specification in the form of a prototype, product, or process. The verb ''to design'' ...

, analyze, simulate, and synthesize ( compile) their designs. In March 2010, Tabula announced their FPGA technology that uses time-multiplexed logic and interconnect that claims potential cost savings for high-density applications. On March 24, 2015, Tabula officially shut down. On June 1, 2015, Intel announced it would acquire Altera for approximately $16.7 billion and completed the acquisition on December 30, 2015. On October 27, 2020, AMD announced it would acquire Xilinx and completed the acquisition valued at about $50 billion in February 2022. Other manufacturers include: * Achronix, manufacturing SRAM based FPGAS with 1.5 GHz fabric speed * Altium, provides system-on-FPGA hardware-software design environment. * Efinix offers small to medium-sized FPGAs. They combine logic and routing interconnects into a configurable XLR cell. * GOWIN Semiconductors, manufacturing small and medium-sized SRAM and Flash-based FPGAs. They also offer pin-compatible replacements for a few Xilinx, Altera and Lattice products. * Lattice Semiconductor, which manufactures low-power SRAM-based FPGAs featuring integrated configuration flash, instant-on and live reconfiguration ** SiliconBlue Technologies, which provides extremely low power SRAM-based FPGAs with optional integrated nonvolatile configuration memory; acquired by Lattice in 2011 * Microchip: ** Microsemi (previously Actel), producing antifuse, flash-based, mixed-signal FPGAs; acquired by Microchip in 2018 ** Atmel, a second source of some Altera-compatible devices; also FPSLIC mentioned above; acquired by Microchip in 2016 * QuickLogic, which manufactures Ultra Low Power Sensor Hubs, extremely low powered, low density SRAM-based FPGAs, with display bridges MIPI & RGB inputs, MIPI, RGB and LVDS outputs

Applications

An FPGA can be used to solve any problem which is computable. This is trivially proven by the fact that FPGAs can be used to implement a soft microprocessor, such as the Xilinx MicroBlaze or Altera Nios II. Their advantage lies in that they are significantly faster for some applications because of their parallel nature and optimality in terms of the number of gates used for certain processes. FPGAs originally began as competitors to CPLDs to implement glue logic for

printed circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich str ...

s. As their size, capabilities, and speed increased, FPGAs took over additional functions to the point where some are now marketed as full systems on chips (SoCs). Particularly with the introduction of dedicated multipliers into FPGA architectures in the late 1990s, applications which had traditionally been the sole reserve of digital signal processor hardware (DSPs) began to incorporate FPGAs instead. The evolution of FPGAs has motivated an increase in the use of these devices, whose architecture allows the development of hardware solutions optimized for complex tasks, such as 3D MRI image segmentation, 3D discrete wavelet transform, tomographic image reconstruction, or PET/MRI systems. The developed solutions can perform intensive computation tasks with parallel processing, are dynamically reprogrammable, and have a low cost, all while meeting the hard real-time requirements associated with medical imaging. Another trend in the use of FPGAs is hardware acceleration, where one can use the FPGA to accelerate certain parts of an algorithm and share part of the computation between the FPGA and a generic processor. The search engine Bing is noted for adopting FPGA acceleration for its search algorithm in 2014. , FPGAs are seeing increased use as AI accelerators including Microsoft's so-termed "Project Catapult" and for accelerating artificial neural networks for

machine learning Machine learning (ML) is a field of inquiry devoted to understanding and building methods that 'learn', that is, methods that leverage data to improve performance on some set of tasks. It is seen as a part of artificial intelligence. Machine ...

applications. Traditionally, FPGAs have been reserved for specific vertical applications where the volume of production is small. For these low-volume applications, the premium that companies pay in hardware cost per unit for a programmable chip is more affordable than the development resources spent on creating an ASIC. , new cost and performance dynamics have broadened the range of viable applications. The company Gigabyte Technology created an i-RAM card which used a Xilinx FPGA although a custom made chip would be cheaper if made in large quantities. The FPGA was chosen to bring it quickly to market and the initial run was only to be 1000 units making an FPGA the best choice. This device allows people to use computer RAM as a hard drive. Other uses for FPGAs include: * Space (i.e. with radiation hardening) * Hardware security modules

Security

FPGAs have both advantages and disadvantages as compared to ASICs or secure microprocessors, concerning hardware security. FPGAs' flexibility makes malicious modifications during

fabrication Fabrication may refer to: * Manufacturing, specifically the crafting of individual parts as a solo product or as part of a larger combined product. Processes in arts, crafts and manufacturing *Semiconductor device fabrication, the process used t ...

a lower risk. Previously, for many FPGAs, the design bitstream was exposed while the FPGA loads it from external memory (typically on every power-on). All major FPGA vendors now offer a spectrum of security solutions to designers such as bitstream encryption and authentication. For example, Altera and

offer

AES AES may refer to: Businesses and organizations Companies * AES Corporation, an American electricity company * AES Data, former owner of Daisy Systems Holland * AES Eletropaulo, a former Brazilian electricity company * AES Andes, formerly AES Gener ...

encryption (up to 256-bit) for bitstreams stored in an external flash memory. FPGAs that store their configuration internally in nonvolatile flash memory, such as Microsemi's ProAsic 3 or Lattice's XP2 programmable devices, do not expose the bitstream and do not need encryption. In addition, flash memory for a lookup table provides single event upset protection for space applications. Customers wanting a higher guarantee of tamper resistance can use write-once, antifuse FPGAs from vendors such as Microsemi. With its Stratix 10 FPGAs and SoCs, Altera introduced a Secure Device Manager and physical unclonable functions to provide high levels of protection against physical attacks. In 2012 researchers Sergei Skorobogatov and Christopher Woods demonstrated that some FPGAs can be vulnerable to hostile intent. They discovered a critical backdoor vulnerability had been manufactured in silicon as part of the Actel/Microsemi ProAsic 3 making it vulnerable on many levels such as reprogramming crypto and access keys, accessing unencrypted bitstream, modifying

low-level High-level and low-level, as technical terms, are used to classify, describe and point to specific goals of a systematic operation; and are applied in a wide range of contexts, such as, for instance, in domains as widely varied as computer scienc ...

silicon features, and extracting configuration data.

Similar technologies

Historically, FPGAs have been slower, less energy efficient and generally achieved less functionality than their fixed ASIC counterparts. A study from 2006 showed that designs implemented on FPGAs need on average 40 times as much area, draw 12 times as much dynamic power, and run at one third the speed of corresponding ASIC implementations. More recently, FPGAs such as the

Virtex-7 or the Altera Stratix 5 have come to rival corresponding ASIC and ASSP ("Application-specific standard part", such as a standalone USB interface chip) solutions by providing significantly reduced power usage, increased speed, lower materials cost, minimal implementation real-estate, and increased possibilities for re-configuration 'on-the-fly'. A design that included 6 to 10 ASICs can now be achieved using only one FPGA. Advantages of FPGAs include the ability to re-program when already deployed (i.e. "in the field") to fix

bugs Bugs may refer to: * Plural of bug Arts, entertainment and media Fictional characters * Bugs Bunny, a character * Bugs Meany, a character in the ''Encyclopedia Brown'' books Films * ''Bugs'' (2003 film), a science-fiction-horror film * ''Bugs ...

, and often include shorter time to market and lower non-recurring engineering costs. Vendors can also take a middle road via FPGA prototyping: developing their prototype hardware on FPGAs, but manufacture their final version as an ASIC so that it can no longer be modified after the design has been committed. This is often also the case with new processor designs. Some FPGAs have the capability of partial re-configuration that lets one portion of the device be re-programmed while other portions continue running. The primary differences between complex programmable logic devices (CPLDs) and FPGAs are

architectural Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing buildings ...

. A CPLD has a comparatively restrictive structure consisting of one or more programmable sum-of-products logic arrays feeding a relatively small number of clocked registers. As a result, CPLDs are less flexible, but have the advantage of more predictable timing delays and FPGA architectures, on the other hand, are dominated by interconnect. This makes them far more flexible (in terms of the range of designs that are practical for implementation on them) but also far more complex to design for, or at least requiring more complex

(EDA) software. In practice, the distinction between FPGAs and CPLDs is often one of size as FPGAs are usually much larger in terms of resources than CPLDs. Typically only FPGAs contain more complex embedded functions such as adders, multipliers,

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered ...

, and serializer/deserializers. Another common distinction is that CPLDs contain embedded

to store their configuration while FPGAs usually require external

non-volatile memory Non-volatile memory (NVM) or non-volatile storage is a type of computer memory that can retain stored information even after power is removed. In contrast, volatile memory needs constant power in order to retain data. Non-volatile memory typ ...

(but not always). When a design requires simple instant-on (logic is already configured at power-up) CPLDs are generally preferred. For most other applications FPGAs are generally preferred. Sometimes both CPLDs and FPGAs are used in a single system design. In those designs, CPLDs generally perform glue logic functions, and are responsible for " booting" the FPGA as well as controlling reset and boot sequence of the complete circuit board. Therefore, depending on the application it may be judicious to use both FPGAs and CPLDs in a single design.

References

External links

* {{Authority control * Integrated circuits Semiconductor devices American inventions Hardware acceleration