Abstract: An external fiber optic cable is snap fit onto the connector of the integrated circuit package, light passes from an optical fiber in the external cable, through the first optical fiber and to the reflecting surface where the light is reflected by the reflecting surface so that it is incident on the photodetector whereas the photodetector converts the light into an electrical signal and the electrical signal is then communicated via a micro pad structures from the optoelectronic die.

Abstract: A method to provide hierarchical reset capabilities for a configurable system on a chip is disclosed. The method includes determining a plurality of reset functions, and establishing a reset hierarchy among the plurality of reset functions.

Abstract: An FPGA includes a programmable interconnect structure in which the interconnect resources are divided into two groups. A first subset of the interconnect resources are optimized for high speed. A second subset of the interconnect resources are optimized for low power consumption. In some embodiments, the transistors of the first and second subsets have different threshold voltages. Transistors in the first subset, being optimized for speed, have a lower threshold voltage than transistors in the second subset, which are optimized for low power consumption. The difference in threshold voltages can be accomplished by using different doping levels, wells biased to different voltage levels, or using other well-known means. In some embodiments, the first subset of the interconnect resources includes buffers coupled to a higher voltage level than the second subset. In some embodiments, the first subset includes buffers manufactured using larger transistors than those in the second subset.

Abstract: A programmable logic device includes a function block to generate a power control signal that is distributed on a rail to selectively power down various components on the device. The rail is coupled to an observation pin to allow for external observation of the power control signal. The power control signal is also provided as a feed forward signal to an input signal blocking circuit, which selectively enables or disables the device input pins in response to the feed forward signal. The feed forward signal is not accessible from the observation pin, and therefore cannot be externally altered from the observation pin.

Abstract: A method and apparatus for reducing jitter in a delay line and trim unit is described. The trim unit includes a plurality of delay elements in parallel. At least one of the plurality of delay elements is controllable between on and off states. At least one of the plurality of delay elements includes at least one filter element to filter local supply noise. At least one of the plurality of delay elements includes a plurality of delay circuits having at least one gated delay circuit to control propagation of a clock signal through the plurality of delay circuits. The plurality of delay elements are configured to maintain an overall propagation delay without adding additional circuitry by sizing at least one delay circuit to provide longer propagation delay and sizing the other delay circuits to provide smaller propagation delay. The plurality of delay circuits are sized and arranged to minimize jitter.

Abstract: A method and apparatus for test vector compression is described. More particularly, a response analyzer is described having a shift register and a multiple-input signature register. The shift register is used to perform a first vector space reduction, and the MISR is used to perform a second vector space compression. Accordingly the MISR may be scaled down in input width by a reduction factor of the shift register.

Abstract: Counter-based duty cycle correction (DCC) circuits and methods. A first counter is periodically enabled to count for one input clock period. After completion of the count, the result is divided by two and stored in a register. Thus, the value stored in the register represents a point halfway through the input clock period. Each time the input clock signal changes from a first state to a second state, an output clock generator also changes the output clock signal from the first state to the second state, and the second counter is enabled. A comparator compares the value in the second counter to the value stored in the register. When the second counter has reached the value stored in the register, the half-way point of the input clock cycle has been reached, and the output clock generator changes the output clock signal from the second state back to the first state.

Abstract: Delay lock loops (DLLs) that include delay line circuits with an optional clock pulse width restoration feature, and programmable delay circuits that enable the DLLs. A DLL can include optional inversions before and after at least one of the delay lines included in the DLL. Because two inversions are provided, the overall logic of the delay line is preserved. A DLL typically includes several different delay lines. Therefore, by selectively inverting the clock signal between the delay lines, the effect of each delay line on the clock pulse width can be balanced to provide an output clock signal having a pulse width closer to that of the input clock than would be achievable without the use of such selective inversion. In embodiments where the DLL forms a portion of a programmable logic device (PLD), the optional inversions can be controlled, for example, by configuration memory cells of the PLD.

Abstract: A method and apparatus to accelerate the evaluation of complex, computationally intense digital signal processing algorithms is disclosed. In one embodiment, a filter accelerator is connected in parallel with a conventional digital signal processor (DSP). The accelerator enhances the speed at which the DSP performs some filtering operations by calculating and maintaining a number of partial results based on a selected number of prior data samples. Each time the DSP receives a new data sample for filtering, the DSP makes use of one or more partial results from the accelerator to speed the calculation of the filtered result. Receipt of the new data sample causes the accelerator to recalculate the partial results, this time using the new data sample. The accelerator thus prepares for receipt of the subsequent data sample, freeing the DSP to perform other operations.

Abstract: A method and test configuration for performing a gross input leakage test at wafer sort is described. The method uses a pullup and pulldown on an I/O pad to inject current at the I/O pad, and, based on the resulting voltage, determines if the leakage current is excessive. The method allows an input leakage test to be performed at wafer sort without a precision measurement unit and without direct access to the I/O pad to be tested.

Abstract: Application of network flow techniques to constrained optimization problems is disclosed. The present of constrains may lead to infeasible solutions. The infeasible solutions can be removed by an iterative process of changing the structure of the network and/or the associated parameters. Specific applications of the invention to the placement of tristate buffers and clocks in integrated circuits are disclosed.

Abstract: Novel structures for implementing wide multiplexers from user designs in FPGA CLBs. Input multiplexers providing the function generator data input signals are modified to function not just based on values stored in configuration memory cells, but also under the control of user signals. Thus, the input multiplexers of the invention are much more flexible than traditional input multiplexers. In one embodiment, the improved data input multiplexer is provided on two of four data input terminals of the function generator, enabling the implementation of an 8-to-1 multiplexer using only a single function generator. Another embodiment applies the concept of mixed memory cell and user control of a multiplexer to the general interconnect structure of an FPGA.

Abstract: A voltage of an input analog signal (105 or 405) can be converted to a signal whose frequency is dependent upon the analog input signal (135 or 435). A frequency divider (115 or 415) can be configured to convert the frequency dependent signal to a frequency divided signal (140 or 440). A first frequency detector (420a) or time detector (120a) can be configured to determine the frequency of the frequency divided signal, thereby creating a first output signal (145a or 445a). A second frequency detector (420b) or time detector (120b) can be configured to determine the frequency of the frequency dependent or non-frequency divided signal, thereby creating a second output signal (145b or 445b). The first and second output signals can be post-processed to generate a digital output signal (130 or 430) that is representative of the input analog signal.

Abstract: A method, apparatus, and system for providing accurate level shifting, residue multiplication, and sample-and-hold functions for ADCs, while eliminating capacitor mismatch as a source of ADC errors. An input signal is sampled onto a first capacitor, and the complemented input signal is sampled onto a second capacitor. The sampled input signal is provided to a first input terminal of a unity gain amplifier by controllably connecting the first capacitor between the amplifier output and the first input terminal. An inverted version of the sampled complemented input signal is level shifted and provided to the amplifier's second input terminal by controllably coupling the second capacitor between a selected level-shift voltage and the second input terminal. The sampled analog input signal is added to the inverted version of the sampled complemented analog input signal, while subtracting the selected level-shift voltage, to provide a residue signal available for use in subsequent conversion stages.

Abstract: A test arrangement is designed to test whether one in a chain of vias or contacts has abnormally high resistance. The arrangement contains a plurality of via or contact chains and a plurality of decoders. The chains are switchably connected to a resistance measurement device. Each decoder has a unique address such that it will generate a control signal when a predetermined address is address thereon. The control signal is used to close a switch, which connect one of the chains to the resistance measurement device. By sequentially applying different addresses to the decoders, the resistance of the chains can be individually measured.

Abstract: Method and apparatus are described for providing memory cells enhanced for resistance to single event upsets. In one embodiment, transistors are coupled between cross coupled inverters of a latch, thus in a small area providing both single-event-upset resistivity most of the time, and high speed during writing to the memory cell. Alternatively, inductors coupled between inverters of a latch may be used.

Abstract: Method and apparatus are described for providing memory cells enhanced for resistance to single event upsets. In one embodiment, transistors are coupled between cross coupled inverters of a latch, thus in a small area providing both single-event-upset resistivity most of the time, and high speed during writing to the memory cell. Alternatively, inductors coupled between inverters of a latch may be used.

Abstract: Interconnecting logic provides connectivity of an embedded fixed logic circuit, or circuits, with programmable logic fabric of a programmable gate array such that the fixed logic circuit functions as an extension of the programmable logic fabric. The interconnecting logic includes interconnecting tiles and may further include interfacing logic. The interconnecting tiles provide selective connectivity between inputs and/or outputs of the fixed logic circuit and interconnect of the programmable logic fabric. The interfacing logic, when included, provides logic circuitry that conditions data transfers between the fixed logic circuit and the programmable logic fabric. In one operation, the programmable logic fabric is configured prior to the startup/boot sequence of the fixed logic circuit. In another operation, the fixed logic circuit is started up and is employed to configure the programmable logic fabric.

Abstract: Method and apparatus for doubling the throughput rate of data transmission on a logic path comprising providing two latches that alternately receive successive bits of the data stream to be transmitted and a multiplexer having data transmission paths that are alternately clocked by two separate clocks, which clocks are substantially 180 degrees out of phase.

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.