Abstract: A limiting circuit includes an input transconductance stage, an output transconductance stage, a feedback transconductance stage, first and second resistive loads, and a level limiting circuit. The input transconductance stage is operably coupled to convert an input voltage signal into an input current signal. The first resistive load is operably coupled to convert the input current signal and a feedback current signal into an intermediate output voltage signal. The output transconductance stage is operably coupled to convert the intermediate output voltage signal into an output current signal. The second resistive load is operably coupled to convert the output current signal into an output voltage signal. The feedback transconductance stage is operably coupled to produce the feedback current signal based on the output voltage signal. The level limiting module is operably coupled to limit at least one voltage level of the feedback transconductance stage.

Abstract: Polysilicon or other material is directionally trimmed using two layers of photoresist and a photoresist etching process, such as ashing. A first layer of photoresist is patterned on a wafer. Portions of the first patterned photoresist are covered with a second layer of photoresist. The photoresist is trimmed to reduce the size of the exposed portions of the first patterned photoresist without reducing the size of the covered portions of the first patterned photoresist. The second layer of photoresist is removed. The selectively etched patterned first layer of photoresist is used as a process mask to define a structure in the underlying material. In a particular embodiment, the second photoresist covers endcap portions of gate photoresist. Directional trimming reduces the width of a polysilicon gate structure (i.e. gate length) over an active area of an FET, without reducing the length of original first patterned photoresist.

Abstract: An input circuit includes a first buffer having a first power terminal coupled to a first supply voltage, a second power terminal coupled to ground potential, an input to receive an input signal, and an output to generate a first output signal, a second buffer having a first terminal coupled to a second supply voltage, a second terminal coupled to a bias node, an input to receive the input signal, and an output to generate a second output signal, and a control circuit configured to selectively connect the bias node either to the second supply voltage or to ground potential in response to an enable signal.

Abstract: Methods and circuitry are disclosed for decoding a keystream. A set of test bits is generated, and a set of attempted keystream bits are generated from differences between the test bits and an input set of cipher bits. A set of current keystream bits are generated from a current seed using a parallel feedback shift register, and the attempted keystream bits are compared to the current keystream bits. In response to attempted keystream bits being equal to the current keystream bits, the current keystream bits are fed back as a new current seed. In response to attempted keystream bits being not equal to the current keystream bits, the attempted keystream bits are fed back as the new current seed.

Abstract: Adjustment circuitry in a phase-locked loop (PLL) adjusts a sampling point to any desired location within a bit period of each bit of received high-speed serial data. The adjustment circuitry, responsive to program control, selectively adds current portions to a charge pump error current output thereby adjusting a feedback signal frequency to shift the serial data sampling point. A plurality of current mirror devices is scaled, with respect to a reference current device, to provide ?I current portions. A current control module controls the current portions magnitude and a sign of the current portions. The adjustment circuitry further controls charge pump programmable current sources in order to set a desired operating point of the PLL. The programmable current sources are controlled by a bias voltage and a plurality of selectable serial and parallel coupled resistors.

Abstract: Various approaches for indicating completion of configuration of programmable logic devices are disclosed. In one embodiment, a plurality of configuration memory cells are arranged for storage of a configuration bitstream for implementing a circuit design on the programmable logic circuit. A plurality of configurable resources are coupled to the configuration memory cells, and each configurable resource implements a function based on data stored in one or more of the configuration memory cells coupled to the configurable resource. A logic circuit is coupled to a subset of the configuration memory cells and is configured to assert a done signal in response to states of the subset of the configuration memory cells.

Abstract: Method and apparatus for timing modeling is described. More particularly, sub-processes for obtaining timing information are described. Each of these sub-process is limited to a portion of a gasket module for coupling an embedded device to a host device, and each of these sub-process may be limited to a lithographic process dimension or adjusted accordingly. By dividing timing information gathering into sub-process, output from each of the sub-process may be combined with timing information provided with an embedded core to determine path delays.

Abstract: A serializer-deserializer instantiated in configurable logic of an integrated circuit is described. The serializer-deserializer includes an input deserializer and an output serializer, which may be commonly coupled via an input/output pad. Each of the serializer and deserializer may be configured for an operating mode selected from a Single Data Rate mode and a Double Data Rate mode. The serializer-deserializer may be used as part of a synchronous interface.

Abstract: Described are fast synchronous counters with reduced combinatorial logic. In one embodiment, a four-bit shift register is configured in a ring and preset with a data pattern (e.g., 1000). The register is then rapidly shifted into any of four unique states. Combinatorial logic connected to the shift register converts the four unique states into a two-bit binary signal representative of the four states. In the general case, counters in accordance with this embodiment represent N-bit binary numbers using 2N synchronous storage elements. Two or more counters can be combined to produce larger synchronous counters. An up/down counter in accordance with yet another embodiment is connected to a multi-path delay line to create a variable delay circuit. The switching speed of the delay circuit is independent of the number of delay settings. Also advantageous, the delay circuit scales linearly, in terms of power consumption and area, with changes in delay granularity.

Abstract: A configuration circuit includes a latch and a dedicated non-volatile memory cell. The non-volatile memory cell is initially programmed or erased. The latch is then set to store a first logic value by coupling the latch to a first voltage supply terminal in response to an activated control signal. When the control signal is de-activated, the latch is de-coupled from the first voltage supply terminal and coupled to the non-volatile memory cell. If the non-volatile memory cell is programmed, the latch is coupled to a second voltage supply terminal, thereby storing a second logic value in the latch. If the non-volatile memory cell is erased, the latch is isolated from the second voltage supply terminal, and the first logic value remains stored in the latch. The latch can also be directly written through one or more access transistors, thereby facilitating testing.

Abstract: A p-channel non-volatile memory (NVM) transistor is programmed by shifting the threshold voltage of the transistor. The threshold voltage is shifted by introducing a programming current to the gate electrode of the transistor, and simultaneously introducing a negative bias to the transistor. The threshold voltage of the p-channel NVM transistor is shifted in response to the negative bias condition and the heat generated by the programming current. The high temperature accelerates the threshold voltage shift. The threshold voltage shift is accompanied by an agglomeration of material in the gate electrode. The agglomeration of material in the gate electrode is an indication of the high temperature reached during programming. The threshold voltage shift of the p-channel NVM transistor is permanent.

Abstract: Structures and methods for selectively applying a well bias to only those portions of a PLD where such a bias is necessary or desirable, e.g., applying a positive well bias to transistors on critical paths within a user's design. A substrate for an integrated circuit includes a plurality of wells, each of which can be independently and programmably biased with the same or a different well bias voltage. In one embodiment, FPGA implementation software automatically determines the critical paths and generates a configuration bitstream that enables positive well biasing only for the transistors participating in the critical paths, or only for programmable logic elements (e.g., CLBs or lookup tables) containing those transistors. In another embodiment, negative well biasing is selectively applied to reduce leakage current.

Abstract: A transceiver can be used to send and receive data at a lower data rate than the data rate its SERDES is designed to operate. It contains a transmitter interface that receives a first set of data at a lower data rate and delivers a second set of data to the SERDES at a higher data rate. The transceiver also contains a receiver interface that receives a third set of data from the SERDES at the higher data rate and delivers a fourth set of data at the lower data rate. To reduce the minimum transmission serial data rate, one embodiment of the present invention derives a half-speed clock for the transmitter interface. Using the half-speed clock, the transmitter interface supplies data to be transmitted at half the normal rate with respect to a reference clock. As a result, the data rate is reduced. The opposite operation is used for the receiver interface.

Abstract: A configurable voltage bias circuit is used to control gate delays in buffers by adjusting the supply voltage of the buffers. The programmable voltage bias circuit includes a configurable voltage divider, which receives an input supply voltage and generates an output supply voltage, and a configurable resistance circuit, which is coupled between the configurable voltage divider and ground. By using a temperature dependent reference voltage to generate the input supply voltage, the output supply voltage is also made to be dependent upon temperature. The programmable voltage bias circuit of the present invention uses the temperature dependence of the output supply voltage to make the gate delays of the buffer temperature-independent.

Abstract: A JTAG-programmable IC includes a memory array having redundant columns, a partial-width data register, and a full-width bitline register. A programming bitstream is shifted into the data register in discrete portions, with each portion being loaded into the bitline latch before the next portion is shifted into the data register. The programming bitstream portions fill the bitline latch sequentially unless a count indicator for a particular portion matches a predetermined defective column value, in which case that bitstream portion is rerouted to a region of the bitline latch associated with the redundant columns of the memory array. The count indicator is incremented with each new bitstream portion shifted into the data register. Once the programming bitstream is fully loaded into the bitline latch, the data is programmed into a selected row of the memory array in page mode.

Abstract: A method of controlling an antenna system of a wireless communication network having a plurality of cells is disclosed. The method comprises the steps of determining antenna weights to enable communication between a wireless communication network and the wireless communication device within the wireless communication network; storing the antenna weights in a programmable memory associated with the wireless communication network; and providing predetermined stored antenna weights to the antenna system based upon a location of the wireless communication device. A circuit and wireless communication network for controlling an antenna system are also disclosed.

Abstract: An integrated circuit die contains digital circuitry that emits noise (for example, in the audio frequency range) in the form of electromagnetic radiation. The integrated circuit die is provided with a shielded platform above the digital circuitry. The shielded platform has one metal plate that is coupled to an analog supply voltage source and another metal plate that is coupled to an analog ground terminal. The digital circuitry is coupled to a digital supply voltage source. A second die with noise-sensitive analog circuitry is stacked on the shielded platform and is shielded by the shielded platform from the noise. The analog circuitry is powered by the analog supply voltage source. Conductive vias in a predetermined pattern protrude through the shielded platform and provide a standardized way of connecting any one of numerous noise-sensitive second dice to the relatively noisy digital circuitry of the underlying die.

Abstract: All the address lines in a data processing system can be tested by using one or more small memory device that do not occupy the full addressing capability of the address lines. In one embodiment, some of the address inputs of the memory device is connected to different address lines at different times. Instructions are pre-loaded into some locations of the memory device such that the address lines has to be asserted to fetch the instructions for execution. By executing the instructions and appropriately connecting the address lines to the address input, all the address lines can be tested. In another embodiment, some of the locations are pre-loaded with a set of predetermined values. A program then writes another set of predetermined values to associated locations. By reading the values in the locations and compared with the sets of predetermined values, it is possible to determine if the address lines are functioning properly.

Abstract: The present invention allows a user to customize the configuration sequence of a configurable system on a chip (CSoC), thereby adding considerable flexibility to the configuration process. The present invention also provides certain features, transparent to the user, which optimize system resources and ensure the correct initialization of the CSoC. The CSoC leverages an on-chip central processing unit (CPU) to control the configuration process of the configurable system logic (CSL). Advantageously, the CSL configuration memory cells as well as other programmable locations in the CSoC are addressable as part of a system bus address space. The system bus is a multi-use structure that can be used for both configuring and reading of memory cells. In this manner, the CSoC optimizes system resources.

Abstract: Method and system for modeling and automatically generating an embedded system from a system-level environment. A plurality of user-selectable system-level design objects are provided in the system-level environment. Each system-level design object is defined by a system-level function and is selectable by a system-level designer. A plurality of hardware-level design objects are also provided. Each hardware-level design object is configured to generate a hardware definition of a hardware-level function. Each system-level design object maps to one or more hardware-level design objects. A processor design object is provided which defines a processor. In response to selections made by the designer, a system-level design is instantiated in a system-level design file. The system-level design includes user-selected ones of the system-level and processor design objects.