Showing papers on "Programmable logic device published in 1999"

Fpga configurable logic block with multi-purpose logic/memory circuit

Abstract: A logic/memory circuit (LMC) utilized in a configurable logic block (CLB) of a programmable logic device (PLD) that implements an eight-input lookup table (LUT) using an array of programmable elements arranged in rows and columns. A decoder is used to read bit values from one column (e.g., sixteen programmable elements) of the array. In one embodiment, a separate read bit line is provided to facilitate faster read operations. A sixteen-to-one multiplexer/demultiplexer circuit is used to pass selected bit values to an output terminal. The array of programmable elements is programmable both from configuration lines during a configuration mode, and by data transmitted on the interconnect resources through the multiplexer/demultiplexer circuit. In one embodiment, the programmable elements of the array are connected in pairs to product term generation circuitry. Product terms generated by the product term circuitry are passed to a macrocell circuit to perform programmable array logic (PAL) logic operations. In another embodiment, a CLB includes four LMCs and a multiplier circuit such that large amounts of logic are locally implemented, thereby avoiding signal delays associated with transmission over general purposed interconnect resources within a PLD.

Integrated circuit device

Abstract: A personalizable and programmable integrated circuit device including at least first and second programmable logic cells and at least two electrical conductive paths interconnecting the programmable logic cells, at least a portion of which can be removed for personalization of the integrated circuit device.

Configurable processor system unit

Abstract: The configurable processor system includes a processor, an internal system bus, and a programmable logic all interconnected via the internal system bus, on a single integrated circuit.

On-chip logic analysis and method for using the same

Abstract: A programmable logic device (PLD) includes a plurality of logic resources, a plurality of multi-bit configuration memories (MBCMs), and a trigger logic structure. The plurality of MBCMs include multiple memory slices that allow the PLD to switch rapidly between configurations, or contexts. In one embodiment, at least one memory slice configures the PLD into a logic analysis context for providing on-chip testing. In one embodiment, the plurality of logic resources include a plurality of storage elements. State data generated by a user-defined context is stored in the plurality of storage elements. When the trigger logic structure provides a trigger signal, the PLD is reconfigured into the logic analysis context. The logic analysis context reads and processes the state data stored in the plurality of storage elements to test the performance of the user-defined context. In one embodiment, the storage elements are multi-bit micro-registers that store state data generated by a plurality of contexts implemented in the multiple-context PLD.

Chain-connected shift register and programmable logic circuit whose logic function is changeable in real time

Abstract: A shift register having a plurality of circuit cells successively connected in a chain formation is proposed. Each of the circuit cells includes a first inversion gate, a first transmission gate, connected to an output of the first inversion gate, being switched by a clock, and a second inversion gate connected to an output of the first transmission gate. The circuit cell further includes a first P-channel transistor, connected between an output of the second inversion gate and an input of the first inversion gate, being switched by the clock, a second transmission gate, connected to the output of the second inversion gate, being switched by an inversion clock, and a second P-channel transistor, connected to the output of the first transmission gate, being switched by the inversion clock. In the shift register, the plurality of circuit cells are successively connected such that the input of the first inversion gate of the circuit cell is connected to an output of a second transmission gate of a former-stage circuit cell, and the output of the first inversion gate of the circuit cell is connected to an output of a second P-channel transistor of the former-stage circuit cell.

Using roving STARs for on-line testing and diagnosis of FPGAs in fault-tolerant applications

Abstract: In this paper we present a novel integrated approach to on-line FPGA testing, diagnosis, and fault-tolerance, to be used in high-reliability and high-availability hardware. The test process takes place in self-testing areas (STARs) of the FPGA, without disturbing the normal system operation. The entire chip is eventually tested by having (STARs) gradually rove across the FPGA. Our approach guarantees complete testing of programmable logic blocks and interconnect, and provides maximum diagnostic resolution. A new fault-tolerant (FT) technique allows using partially defective FPGA resources for normal operation, providing longer mission life-span in the presence of faults. We also introduce the basic concepts of a new dynamic FT method, spare resources needed to bypass a fault are always in the neighborhood of the located fault, thus simplifying fault-bypassing.

Fundamentals of Digital Logic with Verilog Design

Abstract: Fundamentals of Digital Logic With Verilog Design teaches the basic design techniques for logic circuits. It emphasizes the synthesis of circuits and explains how circuits are implemented in real chips. Fundamental concepts are illustrated by using small examples. Use of CAD software is well integrated into the book. A CD-ROM that contains Altera's Quartus CAD software comes free with every copy of the text. The CAD software provides automatic mapping of a design written in Verilog into Field Programmable Gate Arrays (FPGAs) and Complex Programmable Logic Devices (CPLDs). Students will be able to try, firsthand, the book's Verilog examples (over 140) and homework problems. Engineers use Quartus CAD for designing, simulating, testing and implementing logic circuits. The version included with this text supports all major features of the commercial product and comes with a compiler for the IEEE standard Verilog language. Students will be able to: enter a design into the CAD system compile the design into a selected device simulate the functionality and timing of the resulting circuit implement the designs in actual devices (using the school's laboratory facilities) Verilog is a complex language, so it is introduced gradually in the book. Each Verilog feature is presented as it becomes pertinent for the circuits being discussed. To teach the student to use the Quartus CAD, the book includes three tutorials. Table of contents Chapter 1 Design Concepts Chapter 2 Introduction to Logic Circuits Chapter 3 Implementation Technology Chapter 4 Optimized Implementation of Logic Functions Chapter 5 Number Representation and Arithmetic Circuits Chapter 6 Combinational-Circuit Building Blocks Chapter 7 Flip-Flop, Registers, Counters, and a Simple Processor Chapter 8 Synchronous Sequential Circuits Chapter 9 Asynchronous Sequential Circuits Chapter 10 Digital System Design Chapter 11 Testing of Logic Circuits Chapter 12 Computer Aided Design Tools Appendix A Verilog Reference Appendix B Tutorial 1-Using Quartus II CAD Software Appendix C Tutorial 2-Implementing Circuits in Altera Devices Appendix D Tutorial 3-Physical Implementation in a FPGA Appendix E Commercial Devices Answers Index

Optical memory for computing and information processing

Abstract: The high data transfer rate achievable in page-oriented optical memories demands for parallel interfaces to logic circuits able to process efficiently the data. The Optically Programmable Gate Array, an enhanced version of a conventional FPGA, utilizes a holographic memory accessed by an array of VCSELs to program its logic. Combining spatial and shift multiplexing to store the configuration pages in the memory, the OPGA module is very compact and has extremely short configuration time allowing for dynamic reconfiguration. The reconfiguration capability of the OPGA can be applied to solve more efficiently problems in pattern recognition and digit classification.

Memory interfacing and instruction specification for reconfigurable processors

Abstract: As custom computing machines evolve, it is clear that a major bottleneck is the slow interconnection architecture between the logic and memory. This paper describes the architecture of a custom computing machine that overcomes the interconnection bottleneck by closely integrating a fixed-logic processor, a reconfigurable logic array, and memory into a single chip, called OneChip-98. The OneChip-98 system has a seamless programming model that enables the programmer to easily specify instructions without additional complex instruction decoding hardware. As well, there is a simple scheme for mapping instructions to the corresponding programming bits. To allow the processor and the reconfigurable array to execute concurrently, the programming model utilizes a novel memory-consistency scheme implemented in the hardware. To evaluate the feasibility of the OneChip-98 architecture, a 32-bit MIPS-like processor and several performance enhancement applications were mapped to the Transmogrifier-2 field programmable system. For two typical applications, the 2-dimensional discrete cosine transform and the 64-tap FIR filter, we were capable of achieving a performance speedup of over 30 times that of a stand-alone state-of-the-art processor.

ConCISe: a compiler-driven CPLD-based instruction set accelerator

Abstract: We propose a smart compilation chain in which the compiler is no longer limited by a pre-defined instruction set, but can generate application-specific custom instructions and synthesise them in Field-Programmable Logic. We also present a RISC micro-architecture enhanced by a CPLD-based Reconfigurable Functional Unit (RFU) which supports our compiler approach. The main difference between our smart compiler and similar methods is the ability to encode multiple custom instructions in a single RFU configuration, cross-minimising the logic among them. The objective is to reduce (or eliminate) the reconfiguration overhead and optimise the utilisation of resources. The CPLD core that implements the RFU is based on the Philips XPLA2 architecture. We discuss the advantages of using the XPLA2 instead of conventional FPGAs. Application examples are also presented, which show that our RFU-extended CPU can achieve speed-ups of more than 40% for encryption algorithms, when compared to the standard CPU core alone.

Reconfigurable computing system and method and apparatus employing same

Abstract: A reconfigurable computing system and method of use are provided for interfacing a plurality of application programs running on a host system to one or more hardware objects defined in one or more configuration files. The system includes reconfigurable computing circuitry comprising flexibly configurable circuitry operable for interfacing and implementing one or more hardware objects with one or more of the application programs. The system further includes memory circuitry associated with the reconfigurable computing circuitry for system information storage, and communications interfaces for connecting the reconfigurable computing circuitry and the memory to the host computer. The flexibly configurable circuitry further comprises one or more FPGAs and one or more programmable logic devices (“PLDs”), SRAM and EEPROM memory, and all the necessary connectors and support circuitry. The reconfigurable computing system and method of the present invention can be implemented on either a PCMCIA platform, a PCI platform, or any other bus structure without changing the basic functionality and claimed functionality of the reconfigurable computing system. Additionally, the reconfigurable computing system and method of this invention are well suited to be implemented in a portable computing environment.

Fault emulation: A new methodology for fault grading

Abstract: In this paper, we introduce a method that uses the field programmable gate array (FPGA)-based emulation system for fault grading. The real-time simulation capability of a hardware emulator could significantly improve the performance of fault grading, which is one of the most time consuming tasks in the circuit design and test process. We employ a serial fault emulation algorithm enhanced by two speed-up techniques. First, a set of independent faults can be injected and emulated at the same time. Second, multiple dependent faults can be simultaneously injected within a single FPGA-configuration by adding extra circuitry. Because the reconfiguration time of mapping the numerous faulty circuits into the FPGA's is pure overhead and could be the bottleneck of the entire process, using extra circuitry for injecting a large number of faults can reduce the number of FPGA-reconfigurations and, thus, improving the performance significantly. In addition, we address the issue of handling potentially detected faults in this hardware emulation environment by using the dual-railed logic. The performance estimation shows that this approach could be several orders of magnitude faster than the existing software approaches for large sequential designs.

Rapid Prototyping of Digital Systems

Abstract: From the Publisher: Rapid Prototyping of Digital Systems provides an exciting and challenging laboratory component for undergraduate digital logic and computer design courses. The inclusion of more advanced topics and exercises also makes this an appropriate laboratory text for upper-division courses in digital and programmable logic.. "Design Engineers in industry will find Rapid Prototyping of Digital Systems useful as an introduction to FPLD technology and logic synthesis using commercial CAD tools.

Reconfigurable programmable logic device computer system

Abstract: A reconfigurable computer system based on programmable logic is provided. A system design language may be used to write applications. The applications may be automatically partitioned into software components and programmable logic resource components. A virtual computer operating system may be provided to schedule and allocate system resources. The virtual computer operating system may include a virtual logic manager that may increase the capabilities of programmable logic resources in the system.

Safe and protected execution for the Morph/AMRM reconfigurable processor

Abstract: Technology scaling of CMOS processes brings relatively faster transistors (gates) and slower interconnects (wires), making viable the addition of reconfigurability to increase performance. In the Morph/AMRM system we are exploring the addition of reconfigurable logic, deeply integrated with the processor core, employing the reconfigurability to manage the cache, datapath, and pipeline resources more effectively. However, integration of reconfigurable logic introduces significant protection and safety challenges for microprocess execution. We analyze the protection structures in a state of the art microprocessor core (R10000), identifying the few critical logic blocks and demonstrating that the majority of the logic in the processor core can be safely reconfigured. Subsequently, we propose a protection architecture for the Morph/AMRM reconfigurable processor which enable nearly the full range of power of reconfigurability in the processor core while requiring only a small number of fixed logic features which to ensure safe, protected multiprocess execution.

A dynamically reconfigurable logic engine with a multi-context/multi-mode unified-cell architecture

Abstract: Reconfigurable logic LSIs, such as FPGAs, have been perceived as devices for prototyping and emulation. As the size and speed of FPGAs rapidly increase, however, they have begun to be used in /spl mu/P-based systems as reconfigurable accelerators. The idea is to achieve both hardware efficiency and software programmability by dynamically reconfiguring FPGAs. This idea, reconfigurable computing, provides an attractive solution especially for media/network-centric applications. Various types of reconfiguration scenarios in such applications, however, require logic LSIs to significantly enhance reconfigurability in three respects: (1) agility-reconfiguration may need to take place in very short intervals, say within a hundred /spl mu/P instructions; (2) controllability-reconfiguration may be controlled from an external /spl mu/P or by itself; (3) flexibility-reconfiguration target may be arbitrarily positioned and irregularly shaped. The dynamically reconfigurable logic engine (DRLE) prototype described meets this challenge.

Embedded DRAM for a reconfigurable array

Abstract: A field-programmable gate array, coupled with an on-chip 2 Mb DRAM bank has been designed, to aid in the study of the tradeoffs involved in the design of embedded DRAM for FPGAs. The memory can be used both as configuration storage, enabling reconfiguration in under 5 /spl mu/s, and application data memory, providing application logic executing on the array with up to 2 GB/sec data bandwidth. The variable latency of the DRAM is hidden from the logic by a stall mechanism and an SRAM-like interface.

Context switchable field programmable gate array with public-private addressable sharing of intermediate data

Abstract: A context switching logic cell with public and context private data sharing for use in a context switching system. A context switching logic cell includes a programmable logic unit using configuration bits for implementing programmable logic functions for each context, a context memory for storing and providing results of context dependent logic operations, and carry logic. The context memory includes private registers, public registers and an active register. Each private register corresponds to a context and is addressable only within the corresponding context while public registers are addressable within all contexts and the active register stores results of logic operations for the current context. A context switching logic cell may include a data memory that is accessible within all contexts. The context switching logic cells may be arranged into a context switching logic array for use in a context switching system by level 1 buses and carry bit lines. Logic arrays may be interconnected into pipelines by level 2 buses and bidirectional paths connecting sequentially adjacent logic array. A plurality of pipelines may be interconnected in parallel into a context switching system by a third level bus interconnecting the second level buses of the pipelines and carry lines between the corresponding context switching logic arrays of adjacent context switching pipelines.

Method and apparatus for testing field programmable gate arrays

Abstract: A method of built-in self-testing field programmable gate arrays (FPGAs) including the programmable logic blocks, the programmable routing networks and the programmable input/output cells or boundary ports at the device, board or system level includes testing the programmable logic blocks, reconfiguring a first group of he programmable logic blocks to include a test pattern generator and an output response analyzer, and configuring the programmable routing network into groups of wires under test. This step is followed by generating test patterns propagated along the wires under test and comparing the outputs utilizing the output response analyzer. Based on the result of the comparison a pass/fail test result indication is routed to the associated boundary port. The results from a plurality of output response analyzers can be compared utilizing an iterative comparator in order to reduce the number of boundary ports required during testing.

Arbitrary waveform generator having programmably configurable architecture

Abstract: An arbitrary waveform generator (AWG) for producing an analog output current signal includes a random access memory (RAM), a programmable logic device (PLD), a programmable pattern generator, several digital-to analog converters (DACS) and a current multiplexer. The RAM store data sequences representing the analog waveform to be generated. The pattern generator read addresses the RAM causing it to sequentially read out its stored data sequence to the PLD. The PLD routes selected fields of each data sequence word to one or more of the DACs in response to timing signals provided by the pattern generator. Each DAC produces an output current of magnitude determined by its input waveform and range data. The pattern generator also signals the analog multiplexer to sum currents produced by one or more selected DACs to produce the AWG output waveform. The nature of the AWG output waveform is flexibly determined by the nature of the data sequence and the frequency at which it is read out of the RAM, the manner in which the PLD routes the data sequence to the DACs, the value of the range data supplied to each DAC, and the output pattern generated by the pattern generator. The flexible AWG architecture permits the AWG to be appropriately configured for various combinations of output waveform frequency, bandwidth and resolution requirements.

Programmable logic device architectures

Abstract: A programmable logic device has a plurality of super-regions of programmable circuitry disposed on the device in a two-dimensional array of such super-regions. Each super-region includes a plurality of regions of programmable logic and a region of programmable memory. Each logic region includes a plurality of subregions of programmable logic. Each super-region has associated interconnection resources for allowing communication between the logic and memory regions of that super-region without the need to use, for such relatively local interconnections, the longer-length inter-super-region interconnection resources that are also provided on the device.

Timed automaton models for simple programmable logic controllers

Abstract: We give timed automaton models for a class of Programmable Logic Controller (PLC) applications, that are programmed in a simple fragment of the language Instruction Lists as defined in the standard IEC 1131-3. Two different approaches for modelling timers are suggested, that lead to two different timed automaton models. The purpose of this work is to provide a basis for verification and testing of real-time properties of PLC applications. Our work can be seen in broader context: it is a contribution to methodical development of provably correct programs. Even if the present PLC hardware will be substituted by e.g. Personal Computers, with a similar operation mode, the development and verification method will remain useful.

Embedded configurable logic ASIC

Abstract: An Application Specific Integrated Circuit (“ASIC”) ( 10, 30 and 40 ), which includes at least one hardware, non-programmable functional block ( 12, 14, 16, 18, 22, 32, 44, 46 and 48 ), also includes a programmable logic block (“PLB”) ( 26 ). The PLB ( 26 ) is electrically programmable for performing at least one function that complements a function performed using the hardware, non-programmable functional block ( 12, 14, 16, 18, 22, 32, 44, 46 and 48 ). The presence of the PLB ( 26 ) in the ASIC providing system builders with an opportunity to readily differentiate products within their respective product lines by adding particular functions to the ASIC, and to also functionally differentiate among various products offered by competing system builders.

Reconfigurable logic for table lookup

Abstract: An integrated circuit which contains a processor, and configurable logic with configuration memory such that the configurable logic can emulate a large memory array when the contents of the array are very sparse. This structure allows for fast access and a continuous updating capability while remaining internal to the chip. A methodology for recompressing the contents of the configurable logic while updating the configurable logic is also described.

Programmable logic integrated circuit architecture incorporating a global shareable expander

Abstract: A logic element for a programmable logic device to implement a global shareable expander. The logic element includes logic modules (P0-P4) for implementing combinatorial logic and a register (445). The combinatorial and registered paths of a logic element may be utilized at the same time. The logic modules may be programmably coupled to the register. The output of the register may be programmably coupled through an output buffer (515) to an I/O pad (520) of the integrated circuit. The logic modules may bypass the register and directly programmably couple through the output buffer to the I/O pad. A logic module may be used as a shareable expander by programmably coupling the module through to a global interconnect with other logic modules in LABs coupled to the global interconnect.

Programmable pattern generator

Abstract: A pattern generator includes an address generator, an address topology generator, and a data topology generator. The address generator is adapted to provide a first address having a plurality of address bits. The address topology generator includes a first plurality of programmable logic gates. Each programmable logic gate of the first plurality is coupled to receive at least a subset of the plurality of address bits. The first plurality of programmable logic gates generate a second address having a plurality of modified address bits. The data topology generator is adapted to receive at least a subset of the plurality of modified address bits and generate write data based on the subset of modified address bits. A method for generating a pattern includes generating a first address having a plurality of address bits. A second address having a plurality of modified address bits is generated. The second address is a programmable combination of subsets of the address bits. Write data is generated based on a subset of the modified address bits.

Final design method of a programmable logic device that is based on an initial design that consists of a partial underlying physical template

Abstract: A method of making an integrated circuit (IC) includes establishing an initial design for a field-programmable gate array (FPGA) to be included in the IC that includes programmable connections that can be programmed to implement a desired function; establishing an underlying physical template for the IC wherein at least a portion of the template is based on the initial design for the FPGA; selecting a specific configuration of the programmable connections in the FPGA; performing a manufacturing process of the IC using the underlying physical template, and, during the manufacturing process of the IC, bypassing selected on-state transistors in the FPGA used to implement the specific configuration of the programmable connections with metal connections while conserving the underlying physical template. An IC includes a semiconductor substrate and an FPGA fabricated on the semiconductor substrate. The FPGA has a final design that is based on an initial design contemplated by at least a portion of an underlying physical template used for making the IC. The initial design includes programmable connections that can be programmed to implement a desired function and the final design implements a specific configuration of the programmable connections of the initial design. The FPGA includes a plurality of transistors configured to implement the programmable connections of the initial design, and metal connections configured to bypass selected ones of the plurality of transistors as part of implementing the final design.

Encryption of configuration stream

Abstract: A method of communicating encrypted configuration data between a programmable logic device (PLD) and a storage device is included in one part of the invention. The method includes the following steps. Transmit encrypted configuration data stored in a storage device to the PLD. Decrypt the encrypted configuration data to generate a copy of the configuration data in the PLD. Configure the PLD using the copy of the configuration data. In one embodiment, the PLD transmits a key to the storage device. In another embodiment the key is separately entered into the storage device and the PLD and never transmitted between the PLD and the storage device. In another embodiment, the key is entered only into the PLD. The key is used to encrypt the configuration data.

Programmable logic device

Abstract: A logic cell for a programmable logic device that features a random access memory adapted to selectively function as additional logic functions for the logic cell or one of a several different types of random access memory. For example, the random access memory may be configured to provide AND-OR logic functions or as a 32×1 single input port random access memory, two 16×1 single input port random access memories or a 32×1 dual input port memory.

Digital filter with efficient quantization circuitry

Abstract: An infinite impulse response (IIR) digital filter and method of performing the same is disclosed. The digital filter may be realized by way of a programmable logic device, such as a digital signal processor (75), or alternatively by way of dedicated logic including adders (44, 48, 50, 54, 58, 62, 66, 70, 72) and shifters (46, 52, 56, .60, 64). In either case, addition operations (34) are interleaved among first and second output sample values (yn-1, yn-2), so that the resulting addition (30; 72; 215; 320) may be carried out with adder circuitry of the same precision as the signal input (xn) and signal output (yn). Carry control circuitry (76, 78, 80, 82, 84, 88; 217; 317) is provided to efficiently incorporate magnitude truncation quantization.