In combination with a wheel for a bicycle and the like having an annular rim, a hub rotatable about its axis, and axially offset groups of circumferentially spaced spokes which centrally support the hub on the rim; a wheel decorating ornament comprising an annular, planar sheet of material decorated on opposite sides, axially disposed between the groups of spokes and radially disposed between the rim and the hub.

The Test Access Port and Boundary Scan Architecture

A computer’s memory system is the repository for all the information the computer’s central processing unit (CPU, or processor) uses and produces. A perfect memory system is one that can supply immediately any datum that the CPU requests. This ideal memory is not practically implementable, however, as the three factors of memory capacity, speed, and cost are directly in opposition. By placing smaller faster memories in front of larger, slower, and cheaper memories, the performance of the memory system may approach that of a perfect memory system—at a reasonable cost. The memory hierarchies of modern general-purpose computers generally contain registers at the top, followed by one or more levels of cache memory, main memory (all three are semiconductor memory), and virtual memory (on a magnetic or optical disk). Figure 1 shows a memory hierarchy typical of today’s (1995) commodity systems. Performance of a memory system is measured in terms of latency and bandwidth. The latency of a memory request is how long it takes the memory system to produce the result of the request. The bandwidth of a memory system is the rate at which the memory system can accept requests and produce results. The memory hierarchy improves average latency by quickly returning results that are found in the higher levels of the hierarchy. The memory hierarchy usually reduces bandwidth requirements by intercepting a fraction of the memory requests at higher levels of the hierarchy. Some machines, such as high-performance vector machines, may have fewer levels in the hierarchy—increasing cost for better predictability and performance. Some of these machines contain no caches at all, relying on large arrays of main memory banks to supply very high bandwidth. Pipelined accesses of operands reduce the performance impact of long latencies in these machines. Cache memories are a general solution to improving the performance of a memory system. Although caches are smaller than typical main memory sizes, they ideally contain the most frequently accessed portions of main memory. By keeping the most heavily used data near the CPU, caches can service a large fraction of the requests without needing to access main memory (the fraction serviced is called the hit rate). Caches require locality of reference to work well transparently—they assume that accessed memory words will be accessed again quickly (temporal locality) and that memory words adjacent to an accessed word will be accessed soon after the access in question (spatial locality). When the CPU issues a request for a datum not in the cache (a cache miss), the cache loads that datum and some number of adjacent data (a cache block) into itself from main memory. To reduce cache misses, some caches are associative—a cache may place a given block in one of several places, collectively called a set. This set is content-addressable; a block may be accessed based on an address tag, one of which is coupled with each block. When a new block is brought into a set and the set is full, the cache’s replacement policy dictates which of the old blocks should be removed from the cache to make room for the new. Most caches use an approximation of least recently used

Memory systems

This paper introduces a new hybrid ASIC/FPGA chip architecture that is being developed in collaboration between IBM and Xilinx, and highlights some of the design challenges this offers for designers and CAD developers. We review recent data from both the ASIC and FPGA industries, including technology features, and trends in usage and costs. This background data indicates that there are advantages to using standard ASICs and FPGAs for many applications, but technical and financial considerations are increasingly driving the need for a hybrid ASIC/FPGA architecture at specific volume tiers and technology nodes. As we describe the hybrid chip architecture ,we point out evolving tool and methodology issues that will need to be addressed to enable customers to effectively design hybrid ASIC/FPGAs. The discussion highlights specific automation issues in the areas of logic partitioning, logic simulation, verification, timing, layout and test.

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A hybrid ASIC and FPGA architecture

We take a fresh look at the problems posed by deep submicron (DSM) geometries and re-open the investigation into how DSM effects are most likely to affect future design methodologies. We describe a comprehensive approach to accurately characterize the device and interconnect characteristics of present and future process generations. This approach results in the generation of a representative strawman technology that is used in conjunction with analytical model simulation tools and empirical design data to obtain a realistic picture of the future of circuit design. We then proceed to quantify the precise impact of interconnect, including delay degradation due to noise, on high performance ASIC designs. Having determined the role of interconnect in performance, we then reconsider the impact of future processes on ASIC design methodology.

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Getting to the bottom of deep submicron

Electrical current source circuitry for a bus is described. The circuitry includes transistor circuitry coupled between the bus and ground for controlling bus current, control circuitry coupled to the transistor circuitry, and a controller coupled to the control circuitry for controlling the transistor circuitry. The controller comprises a variable level circuit comprising setting circuitry for setting a desired current for the bus and transistor reference circuitry coupled to the setting circuitry. The variable level circuit provides a first voltage. Voltage reference circuitry provides a reference voltage. Comparison circuitry is coupled to the voltage reference circuitry and to the variable level circuit for comparing the first voltage with the reference voltage. Logic circuitry is responsive to a trigger signal from the comparison circuitry. An output of the logic circuitry is coupled to the control circuitry in order to turn on the transistor circuitry in a manner dependent upon an output of the logic circuitry.

Electrical current source circuitry for a bus

PROBLEM TO BE SOLVED: To provide an electrostatic discharge protective circuit in which triple well semiconductor device is used alone or in series construction. SOLUTION: The semiconductor device is preferably a diode junction construction. When the semiconductor device is used in a series construction, bias application can be controlled by using a control circuit. Regions 3 and 3A are n-doped, elongate up to a n-doped region 8 downwards, and forms a ring so as to separate a p-doped region 6 from a substrate region 10.The regions 3 and 3A can provide insulators of other size to separate the region 6. Moreover, the region 3 and 3A can be formed by using single implantation, or, by using a plurality of implantation of different energy or a quantity of dose. The region 6 is p-doped so as to make a separation from the substrate 10 possible. In this embodiment, a metallic junction of a p-n diode is formed on an area where the p-region 6 is adjacent to the region 3, the region 3A, and the region 8. COPYRIGHT: (C)2004,JPO&NCIPI

Electrostatic discharge protective circuit of triple well semiconductor device

The protection circuit of the present invention addresses the problem of indeterminate logic levels caused by loss of one of the power supplies in a two-power-supply CMOS integrated circuit. The circuit of the present invention replaces the typical scheme of power supply sequencing to fix the problem. The circuit disclosed herein detects the state of the core voltage and disables the output drivers when the core voltage is detected as being off. The disabled drivers are put into a high impedance state, thereby eliminating the potential for damage and eliminating the need for power supply sequencing. The invention also protects against the sudden loss of the integrated circuit core voltage, VDD, power supply during normal operation.

Dual rail power supply sequence tolerant off-chip driver

A method for altering circuit characteristics to make them independent of processing parameters of devices within an integrated circuit is disclosed. A process parameter is measured by a kerf or on-chip built-in test on a selective set of chip on a wafer, and the results are stored on a storage device within each respective chip. Then, for each of the remaining chips, a two-dimensional interpolation is performed to determine the process parameter value for the respective chip based on the measured value. The interpolated values are recorded along with the coordinates of the chip in an efuse control file. Such information is subsequently stored into an efuse module within the chip. On-chip digital control structures are used to adjust certain operational characteristics of a functional component within the chip based on the information stored in the efuse module.

Method and apparatus for storing circuit calibration information

A design structure embodied in a machine readable medium used in a design process includes a voltage divider device, including a double gate field effect transistor (FET) having a first gate and a second gate disposed at opposite sides of a body region; the first and second gates configured to have an input voltage coupled thereacross; and at least one of a source of the FET and a drain of the FET configured to have an output voltage taken therefrom; wherein the output voltage represents a divided voltage with respect to the input voltage.

Design structure for implementing oxide leakage based voltage divider network for integrated circuit devices

A state saving circuit includes a state saving latch powered by an un-interruptible power supply, and a cut-off control device powered by the un-interruptible power supply that selectively connects the state saving latch to a pair of latch nodes based upon a control signal. The control signal determines whether the state-saving latch is in one of a state saving mode and a state restoring mode.

Douglas W. Stout

Papers

Electrostatic discharge protective circuit of triple well semiconductor device

Dual rail power supply sequence tolerant off-chip driver

Method and apparatus for storing circuit calibration information

Design structure for implementing oxide leakage based voltage divider network for integrated circuit devices

High performance state saving circuit