Asynchronous fpga architectures computers and digital. There are several srambased fpga vendors, who introduce multiple new fpga architectures each year. The most probable effect, when we consider srambased fpga at sealevel, is the singleevent upset seu, i. However, if youre interested in fpgas under the hood, then have a look at the virtex6 fpga configurable logic block user guide or the virtex5 fpga user guide. Fpga devices 16 board level and routing skew can be managed. The existing sram based fpga products include the xilinx xc3000, xc4000, and xc5000 families xi94a. To validate and justify our approach, 512 36 hp srambased tcam has been implemented in xilinx virtex5 field programmable gate array fpga and designed using 65nm cmos technology.
Towards a truly srambased fpga online concurrent testing manuel g. In this work, an integrated design of an sram fpga based high. Configuration bitstream reduction for srambased fpgas by enumerating lut input permutations ameer abdelhadi and guy g. A test framework using an exchangeable payload is developed for this purpose and run on a xilinx virtex5 fpga. There are several sram based fpga vendors, who introduce multiple new fpga architectures each year. Smartfusion2 soc fpga sram initialization from envm. Fpga based synchronous multiport sram architecture for. An sram static random access memorybased reprogrammable fpga field programmable gate array is investigated for space applications. This design has been implemented within a single xilinx virtex4 sx35, coupled to a pair of qdr sram chips, on a custom board. Sram based fpga depends on the type of data structure to be protected. Susceptibility of redundant versus singular clock domains. Ternary content addressable memory is a type of memory that allows the memory to be searched by content rather than by address. A model of architecture for the lutram module with n inputs and 2n memory cells is proposed taking into account the lut and ram modes. In particular, srambased fpga devices are employed in many applica tion fields.
Fpga based soc design formulation on an artix7 200t fpga. The fpga configuration data is stored in files called bitstreams that have the. Srambased fpgas require an external nonvolatile memory to hold their configuration pattern, which upon powerup is transferred via serial link into. A new commercial prototype, named the rs family, was used as an example for the investigation. Figure 2 is a highlevel block diagram of the virtex5 fpga qdr ii memory reference design, showing both the external connections to the qdr ii memory device and the internal fpga fabric interface for initiating readwrite commands. Usually, the board will have an eeprom to hold the program bitstream and the fpga will load the bitstream automatically at reset. Fast content updating algorithm for an srambased tcam on fpga. Srambasedfpgasystemsfor safetycriticalapplications. As stated in 1, the logic may be grouped into four different structure types. Abstractrecently, srambased fpgas are widely used in aeronautic. Seu fault evaluation and characteristics for srambased. One supplier of sram based devices has replaced the standard, sixtransistor, functional element with a radiationhardened, 12transistor design shown below. Ternary content addressable memory, tcam is a semiconductor memory device, operates for determining a match between received search data and stored data in tcam bitcells.
Sram based fpgas provide the hardware infrastructure to implement fault injectors taking advantage of dynamic partial reconfiguration. Index terms field programmable gate array fpgabased. Ii slave mode fpga is arranged by an external master device, such as a processor. Configuration bitstream reduction for srambased fpgas by. Single event effects in sram fpga single event upset seu in configuration memory in sram fpga, the circuit itself is stored in a ram. Multiple fault testing of logic resources of srambased fpgas. Faults in the configuration memory of a sram based fpga directly modify the definition of its function, dangerously impacting its ability to operate properly. Fpga architectures overview portland state university. Sram based fpga overview i master mode fpga reads configuration data from an external source, so as an external flash memory chip. Memory basics and timing massachusetts institute of. To validate and justify our approach, 512 36 hp sram based tcam has been implemented in xilinx virtex5 field programmable gate array fpga and designed using 65nm cmos technology. A performancedriven general logic synthesis system for. Finally section4gives results on the performance of the system. Srambased fpga systems for safetycritical applications.
Pdf srambased fpga systems for safetycritical applications. Comparing flash and srambased fpgas electronic products. Pdf fpga implementation of srambased ternary content. The vivado software from xilinx can create bitstreams from vhdl, verilog, or schematicbased source files. Nandy ghoshal indian institute of science bangalore 560 012 india abstract field programmable gate armys represent a very promising technolo y that attempts to provide the ben efits of. How can srambased fpga implement the combination logic. Srambased fpgas provide the hardware infrastructure to implement fault injectors taking advantage of dynamic partial reconfiguration.
Feb 19, 2018 thanks for the a2a, but i honestly cant provide an experienced response to this question. Jun 09, 2014 other spacegrade fpgas contain intrinsic architectural and circuitlevel features to protect against upsets and transients. Throughput logic, statemachine logic, io logic, and special features select block ram, dlls, etc. Power efficient dataaware sram cell for srambased fpga. Other spacegrade fpgas contain intrinsic architectural and circuitlevel features to protect against upsets and transients.
We show that recent sram based fpgas can constitute a. Lemieux department of electrical and computer engineering university of british columbia vancouver, b. A variationtolerant mrambackedsram cell for a nonvolatile. A performancedriven general logic synthesis system. Carter, hsieh 1987, 1990, kean, furtek, hastie, kawana, muroga, ebeling, chow, hauck, hill and britton britton 1993 and cliff have all proposed sramprogrammable fpgas.
Thanks for the a2a, but i honestly cant provide an experienced response to this question. Inputoutput logic based faulttolerant design technique for. Architecture figure1shows the functional architecture of the system. Single event upsets in sram fpga the functionality of a sram fpga is determined by the state of its con. Assessing scrubbing techniques for xilinx srambased.
The proposed work includes a self controllable voltage level svl circuit along with 10t sram cell and asynchronous counters in. Becker, amir moradi, christof paar, fellow, ieee abstractthis contribution is concerned with the question whether an adversary can automatically manipulate an unknown fpga bitstream realizing a cryptographic primitive such that the underlying secret key is. We characterize the startup state of two external, independent srams in order to analyze their suitability as the source of a puf. The point i was trying to make is that all flash based fpgas are not the same. Srambased fpga will be the focus of this work, more specifically the virtex family 17 from xilinx. Sram means the chip programming is held in ram or flops or similar. This paper addresses the problem of testing the ram mode of the lutram modules of configurable sram based field programmable gate arrays fpgas using a minimum number of test configurations. The throughput logic is a logic module of any size or functionality, synchronous. In this paper, we evaluate and compare scrubbing techniques for xilinx srambased fpgas with respect to radiationinduced single event upsets. Srambased fpga re configuration, the main objective. We designed and built a pcb hosting a virtex5 xilinx fpga. Xilinx xapp853 qdr ii sram interface for virtex5 devices.
Further, fpga devices based on sram are the most susceptible to the adverse e. One supplier of srambased devices has replaced the standard, sixtransistor, functional element with a radiationhardened, 12transistor design shown below. Atmel microsemi xilinx the flow has been extended to partially and dynamically reconfigurable system based on xilinx fpgas. For example, im using a fpga dev board from terasic and it uses dram. The c and c pins of the qdr ii memory device are tied high in figure 2. Request pdf multiple fault testing of logic resources of srambased fpgas we present a simple but useful method which detects all multiple stuckat faults in the application and configuration. However, clock skew within a single tree and between different trees is based on the manufacturers product and can be difficult or impossible to control. You usually dont have to bother with luts and flipflops, especially not at the beginner level. An fpgabased stream processor for embedded realtime vision. Static random access memory sram, which is internal to many fpgas, has been proposed as a source of this puf 3. Fast content updating algorithm for an srambased tcam.
Seu fault evaluation and characteristics for srambased fpga. Smartfusion2 soc fpga sram initialization from envm 4 revision 5 page 16 start address 0x800 is used here for demonstration purposes. Flashbased vs srambased fpga most important con of sram based fpga. An fpgabased stream processor for embedded realtime. Sram based reprogrammable fpga tbr space applications.
Although dram memory seems to be cheaper that sram static ram, from my point of view it is not optimized for image processing, let me explain. Seu recovery mechanism for srambased fpgas computer. On the optimal design of triple modular redundancy logic for. How can sram based fpga implement the combination logic. Assessing scrubbing techniques for xilinx srambased fpgas. Automated fault attacks against srambased fpgas pawel swierczynski, georg t. Assessing scrubbing techniques for xilinx srambased fpgas in. Xilinxs 3an series are multidie solutions with a standard. Since their introduction, sramprogrammable fpgas have become very popular. This recon figurability is being used in a new class of fpga based.
Politecnico di torino fpga cad flow the flow is currently applied to the following fpga families. Pdf fpga based architecture for high performance sram. On the other hand, srambased fpgas need a supporting nonvolatile memory to store the con. Designing fault tolerant systems into srambased fpgas. The most probable effect, when we consider sram based fpga at sealevel, is the singleevent upset seu, i. In this paper, we evaluate and compare scrubbing techniques for xilinx sram based fpgas with respect to radiationinduced single event upsets. The design of an srambased fieldprogrammable gate array. Why are sram fpgas used if they are volatile, and for what. Systemc language reference manual was published early in 2012 iee12. Sram characteristics as physical unclonable functions. Problem statement stateoftheart sram based fpgas provide a large amount of con. Flash based vs sram based fpga most important con of sram based fpga.
Sram based fpgas require an external nonvolatile memory to hold their configuration pattern, which upon powerup is transferred via serial link into. Fpga based ternary content addressable memory using sram. Single event upset mitigation techniques for sram based. However, power consumption is exceptionally critical in these devices, since unlike asics, sram based fpgas are composed of several resources such as logic blocks. Multiple fault injection platform for srambased fpga based. Counter matrix code for sram based fpga to correct multi. This design has been implemented within a single xilinx virtex4 sx35, coupled to a pair of qdrsram chips, on a custom board. Xilinxs 3an series are multidie solutions with a standard srambased part and a spi flash packaged together. Pdf as the asic design cost becomes affordable only for very largescale productions, the fpga technology is currently becoming the. Jun 25, 2009 the point i was trying to make is that all flash based fpgas are not the same. This is the most commonly used architecture among academic and commercial fpgas. Fpga architectures overview in this short article we discuss modern fpga architectures srambased, flashbased, antifusebased and their applications. Fpga is based on 10t static random access memory sram cell configuration in which power consumption is relatively high.
Bitstreams are stored in srambased memory cells within the fpga. Faults in the configuration memory of a srambased fpga directly modify the definition of its function, dangerously impacting its ability to operate properly. We exploited high stability oscillators to test the two different architectures. Soft errors in partially and dynamically reconfigurable sram. A generic methodology to compute design sensitivity to seu in. 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. The design of an sram based fieldprogrammable gate array part i. It performs high speed lookup operations within a single clock cycle. Final considerations and future work conclude the paper. The two methods ought to be used for time interpolation within the system clock cycle. Lattices are really srambased using a mixed sram flash process with backup storage in the onchip flash.
Srambased fpga depends on the type of data structure to be protected. A new reconfigurable clockgating technique for low power. Clock skew was less of a problem in smaller xilinx fpga devices e. Dram data is accessed by block, sram data can be accessed addressed byte by byte or word by word, or 36 bit at a time, whatever. Static ram sram cell the 6t cell wl bl vdd m5 m6 m4 m1 m2 m3 bl q q state held by crosscoupled inverters m1m4 retains state as long as power supply turned on feedback must be overdriven to write into the memory wl bl bl wl q q write.
The existing srambased fpga products include the xilinx xc3000, xc4000, and xc5000 families xi94a. However, if youre interested in fpgas under the hood, then have a look at the virtex6 fpga configurable. On the optimal design of triple modular redundancy logic. Fault injection by emulation is a wellknown method to analyze the reliability of a circuit. Mar 07, 2015 sram means the chip programming is held in ram or flops or similar. Although ive used xilinxbased sram fpgas, and latticebased flashcplds, i dont think i can give you much of a nuanced response, other than the following. As a result, srambased fpgas offer the additional benefits of allowing inorbit design changes, with the aim of reducing the mission cost by correcting errors or improving system performance after launch. But when compared to ram technology the conventional tcam circuitry has certain limitations such as low access time, low storage capacity, circuit complexity and high cost. Architecture paul chow, member, ieee, soon ong seo, jonathan rose, member, ieee, kevin chung, gerard p. When a seu occurs in the combinational logic synthesized in the fpga, it corresponds to a bit. How does srambased fpga differ from antifusebased fpga. Bitstreams are stored in srambased memory cells within. Alves department of electrical engineering isep rua dr. In srambased fpgas, customizable memory cells sram cells, implement both the users combinational and sequential logic.
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