They use an antifuse cmos technology and once the fpga has been programmed, it cannot be reprogrammed. However, there are several fundamentally different ways to build an fpga. The antifuse technology, routing architecture, logic mod ule, design automation, programming, testing and use of acttm antifuse fpga s are described. Creating fpgabased designs introduces a wide range of different design flows, tools, and concepts with lots of juicy technical details that only an engineer could love. Pdf design of 1 kbit antifuse one time programmable. General antifuse programming information programming features for soc products group devices soc products group provides two types of fpgas. Antifuse programming technology fpgas this page was last edited on 7 julyat each bit contains both a fuse and an antifuse and is programmed by triggering one of the two.
However, antifuses can be selectively grown by applying pulses of relatively high voltage and current as illustrated in fig. In particular, antifusebased fpgas offer higher security, stemming primarily from their nonvolatility 14. A fieldprogrammable gate array fpga is an integrated circuit designed to be configured by a customer or a designer after manufacturing hence the term fieldprogrammable. Because aerospace applications typically involve long operating life, there is a requirement to store unprogrammed antifuse fpga parts for long periods and program them when necessary to support the system. If the processor is the new lut, what about processor arrays. Each bit contains both a fuse and an antifuse and fpgws programmed by triggering one porgramming the two. Antifuse programming technology fpgas in the same fashion as with the christmas lights described above, if the lamp failed, the entire voltage of the street lighting circuit thousands of volts was imposed across the insulating film in anifuse cutout, causing it to rupture. Fpgas are a powerful tool well known to embedded systems engineers. How to program an fpga programming fpgas electronics notes. This rapidly causes the antifuse to short out the blown bulb, allowing the series circuit to resume functioning, albeit with a larger proportion of the mains voltage now applied to each of antivuse remaining lamps. In antifuse fpgas, as fuses are programmed, it becomes impossible to uniquely address previously programmed fuses making programming essentially a oneway function. Antifuse programming fpgas pdf fpga field programmable gate array is an integrated circuit fpga devices are produced by a number of semiconductor basic modes of programming.
Antifuses are origi nally opencircuits and take on low resistance only when programmed. Antifuse field programmable gate arrays ieee xplore. Silicon carbide sic nanoelectromechanical antifuse for. Design security in nonvolatile flash and antifuse fpgas. Srambased fpgas are volatile and need to be reprogrammed at each powerup. An adaptive faulttolerant memory system for fpgabased. Silicon carbide sic nanoelectromechanical antifuse for ultralow. The fpga enables the functionality of the chip to be programmed in, enabling this to be updated at any point required.
A 1 kbit antifuse one time programmable otp memory ip, which is one of the nonvolatile memory ips, was designed and used for power management integrated circuits ics. Fpgas programming technology basic logic cells io logic cells programmable inter connect software to design and program the fpga. The fpga configuration is generally specified using a hardware description language hdl, similar to that used for an applicationspecific integrated circuit asic. It is an open path until a programming current is forced through it by applying a high programming voltage across it. Many such technologies have been considered for use in fpgas, including laser programming, pass transistors controlled by sram or eprom cells and antifuses. Testing and programming actel field programmable gate arrays fpgas 7 this can be done by programming a special type of antifuse referred to as a horizontal antifuse. Static memory is the most widely used method of configuring fpgas. Antifusebased fpgas antifusebased fpgas are different from the previous ones in that they can be programmed only once. The antifuse is a device that doesnt conduct current initially, but can be burned to conduct current the antifuse behavior is thus opposite to. Actel calls its antifuse a programmable lowimpedance circuit element plice. While antifusebased fpgas are currently among the most secure programmable. You can copy this pdf to your computer so as to be able to access the design warriors guide to fpgas as required this is particularly useful if you travel a lot and use a notebook computer. Fpga is the densest and most advanced programmable logic device.
Modern fpgas can be tied to a large variety of io types. Realtime device verification actels antifuse fpgas contain actionprobe circuitry, sharp ccd sensor lens lcd display consumptionand they find that actels antifuse fpgas for, the mp3 market leader. Sram means the chip programming is held in ram or flops or similar. Design security in nonvolatile flash and antifuse fpgas microsemi. Some programming methods are common to both and some are exclusive to flash. Antifuse programming need to be able to apply programming voltage to every antifuse. In this way, the failed lamp was bypassed and illumination restored to the rest of the street. Reprogrammability makes development much easier, as new designs can be programmed into the same part over and over again.
Fieldprogrammable gate array technology describes the major fpga architectures available today, covering the three programming technologies that are in use and the major architectures built on those programming technologies. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. There is no bootup period while data is being downloaded from an external device. Dynamic burnin is the most effective way to exercise all the active elements as a built configuration. This document describes only the programming solutions supported for antifuse devices. When the programmiing blows, the entire mains voltage is applied across the single blown lamp. Actels antifuse fpgas already have the advantage of being a singlechip.
It secures a design due to piracy and difficulty in determining the state of an. Antifuse invented at stanford and developed by actel. Programming current controls the antifuse resistance typically for 5ma it is 500 ohms. The other type of programmable switch used in fpgas is the antifuse. Spacegrade fpgas are offered in three major process technologies. Antifuse devices are mainly programmed using singlesite or multisite programmers. Fpga architectures overview in this short article we discuss modern fpga architectures srambased, flashbased, antifusebased and their applications. Antifuse programming technology an antifuse is the opposite of a regular fuse. Wang actel corporation, mountain view, ca 94043, usa jihjong. An srambased fpga is a volatile device that must be initialized or programmed at each powerup cycle. How does srambased fpga differ from antifusebased fpga.
Therefore, we will discuss combinational logic and interconnect for the two major styles of fpga. Security types and implementation are discussed in the implementation of security in microsemi antifuse fpgas application note. There is a brief discussion of the programmable element impact on the. Srambased fpgas are based on the newest commercially available manufacturing processes and therefore have supe. Other legacy devices listed may still be in full production, but there may be available pincompatible. First, once a device is programmed, it cannot be changed. In this short article we discuss modern fpga architectures srambased, flashbased, antifuse based and their applications. Legacy devices are fpgas that microsemi no longer recommends for new designs. This can be changed to accommodate updates or to even change the functionality a board or system when it is required to perform different functions.
Effective postprogramming screening of antifuse fpgas for. Antifuse programming technology fpgas when the bulb blows, the entire mains voltage is applied across the single blown lamp. No study on the long term reliability of unprogrammed antifuse fpgas in the storage environment is reported in literature. Programming mec fpgas with old algorithms resulted in possible damage to antifuse from overheating during the programming operation. Some fpgas are antifusebased allowing them to only be one time programmable devices otps and sram based, which can be programmed as many times as required. This eases prototyping and allows devices to be completely reconfigured inorbit. Srambased fpgas, however are worth considering as an alternative to antifuseprogrammed fpgas. Thus the architecture of the antifusebased devices makes electronic readback impossible.
Antifuse technology is nonvolatile, so it is live at powerup and inherently very secure. Assessing and mitigating radiation effects in xilinx fpgas. Fpga fabrics 3 fpga fabrics architectures of fpgas sram. Otp technology 06022003 uahcpe528 8 antifuse contd. The insulation of the antifuse wire withstands the ordinary low voltage imposed across a functioning lamp but rapidly breaks down under the full mains voltage, giving the antifuse action. In its unprogrammed state, an antifuse has such a high resistance that it may be considered an open circuit a break in the wire, as illustrated in fig. Usually, the board will have an eeprom to hold the program bitstream and the fpga will load the bitstream automatically at reset. Testing and programming actel field programmable gate. We will start with a brief introduction to the structure of fpga fabrics. Use the wiring network to gain access to the antifuses. This means that cplds can be up and running when power is applied and are nonvolatile. Introduction fpga field programmable gate array is an integrated circuit containing gate matrix which can be programmed by the user in the field without using expensive equipment. Why did dynamicallyprogrammed fpgas never go anywhere.
Understanding actel antifuse device security digchip. The architecture of an fpga is determined, in large part, by the programmable switch technology used to configure it. Programming technologies and architectures of fplds. Pdf a test methodology for interconnect structures of. This is not the case for antifusebased fpgas which are. Antifusebased fpgas are different from the previous ones in that they can be. As a result, srambased fpgas have historically been less desirable for use in critical spacecraft electronics. As an example, the output of module 3 is also connected to the input of module 1 by programming two crossantifuses and one horizontal antifuse. Fpga field programmable gate array is an integrated circuit containing gate. See imperial college, 2005 digital system design 3. In addition to internal capabilities, external interfaces to the fpga are also important. The reader is introduced to concepts relevant to the entire field of fpgas using popular devices as examples. Thus the architecture of the antifusebased devices makes electronic readback impossible, even if the locking mechanism is not used. Pdf tq100 cs180 tq144, fg144 188899actel actel fpga tms.
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