Abstract: The invention relates to an integrated bus signal hold cell that is coupled with a bus line via a common input/output, and that has at least two inverters for holding the last state of the bus line. The outputs of the inverters are coupled with each other's inputs, respectively. The input of the first inverter is coupled with the input/output. The output of the second inverter is coupled with the input/output. An additional input is provided via which the bus signal hold cell can be charged with a defined test signal. The invention also relates to an integrated bus system and a method for driving a bus signal hold cell and a bus system.

Abstract: The present invention provides a clock signal feeding circuit that suppresses performance degradation under the worst operating conditions. A clock signal CLK is fed, via a delay buffer with a capacitor as a delay element, to a FF disposed in the upstream of a logic circuit block having the longest processing time, and a clock signal CLK is fed, via a delay buffer with a transistor as a delay element, to a FF disposed in the downstream of the logic circuit block having the longest processing time. If the processing time of the logic circuit block increases due to factors such as variations in operating environment, and thus outputting of data representing the operation result delays, the timing of the clock signals fed to the FFs also delays due to the same factors.

Abstract: A 2-input AND gate is inserted between an output terminal of a scan flipflop with an input selectable gate and a logic output signal line. The 2-input AND gate is controlled by a scan-enable signal line, and has a role to fix the transition of the output signal of the scan flipflop.

Abstract: A flip flop (30) comprising a master stage (34) comprising a first plurality of transistors (54, 56), wherein each of the first plurality of transistors comprises a selective conductive path between a source and drain. The flip flop also comprises a slave stage (42) comprising a second plurality of transistors (60, 62, 64, 66), wherein each of the second plurality of transistors comprises a selective conductive path between a source and drain. For the flip flop, in a low power mode the flip flop is operable to receive a first voltage (VDD) coupled to the selective conductive path for each of the first plurality of transistors. Also in the low power mode, the flip flop is operable to receive a second voltage (VDDL) coupled to the selective conductive path for each of the second plurality of transistors. Lastly, the second voltage is greater than the first voltage in the low power mode.

Abstract: Chemically assembled electronic nanotechnology (CAEN) provides an alternative to using Complementary Metal Oxide Semiconductor (CMOS) for constructing circuits with feature sizes in the tens of nanometers. A molecular latch and a method using the latch that enables it to act as a state holding device, perform voltage restoration, and to provide I/O isolation is disclosed.

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: A testable, prechargeable circuit has a driving circuit for producing a driving circuit output signal. A timing circuit receives a clock signal and the driving circuit output signal to cause an output of the testable, prechargeable circuit to be in a low state when the clock signal is low. The timing circuit also causes the output of the circuit to be timed with a state change in the clock signal to provide a domino logic output signal. Either a data signal or a test signal are multiplexed to the input of the driving circuit to produce respectively the domino logic output signal or a test output signal. A static logic circuit receives the test output signal to produce a test signal output.

Abstract: The present invention provides a fault-tolerant inverter circuit, comprising a signal input point for receiving the input signals. A first inverter, the input end of the first inverter connects to the signal input point. A second inverter, the input end of the second inverter connects to the output end of the first inverter. A third inverter, the input end of the third inverter connects to the output end of the second inverter. A signal output point, and it is used to connect the output end of the third inverter. A first conducting wire, the two ends of which connect respectively to the signal input point of the first inverter and the output end of the second inverter. A second conducting wire, the two ends of which connect respectively to the outputting end of the first inverter and the signal output point. Therefore, the fault-tolerant inverter of the present invention provides fault-tolerance when an opening occurs in any conducting wire or transistor.

Abstract: One embodiment of the present invention provides a system that facilitates fully characterizing propagation delay through an n-input circuit. The system operates by first receiving the n-input circuit. Next, the system establishes programmable voltage sources at each input of the n-input circuit. The system then programs each programmable voltage source to provide a sequence of input patterns to the n-input circuit. This sequence includes the 22n possible transitions between all possible pairs of input patterns. Next, the system measures the propagation delay between the input and the output of the n-input circuit for each transition in the sequence of input patterns and then reports the results.

Abstract: A programmable data latch (21) is disclosed. The data latch comprises a master latch (34) operable to load data into the data latch (21) and a slave latch (36) operable to receive the data and produce the output (20) and inverted output of the data latch (21). Also provided is a plurality of programmable floating gate transistor (53, 54) wherein the “on” or “off” state of the floating gate transistor (53, 54) is determined by the data loaded into the data latch (21). A programming voltage supply (26) is supplied to the floating gate transistors (53, 54) which increases the threshold voltage of the floating gate transistor (53, 54) in the “on” state and produces a programmed transistor. The programmed transistor is operable to set the state of the data latch (21) upon subsequent use.

Abstract: The present invention encompasses a bus hold and weak pull-up circuit. A resistor having a first node and a second node is coupled to a bi-directional I/O pin at the first node. The weak pull-up circuit is directly coupled to the resistor at the first node. The bus hold circuit is coupled to the resistor at the second node.

Abstract: The invention relates to a semiconductor module having a plurality of signal paths for carrying external signals that each contain a setup and hold circuit on the basis of a latch circuit with a full latch and a logic circuit. The latch circuit contains at a beginning of the signal path upstream of the logic circuit a hold latch. The hold latch responds to the leading edge of a fast clock signal derived from the clock signal of the external signal, for the early latching of the external signal and for the decoupling of the hold time from the setup time. The full latch is disposed downstream of the logic circuit for the final latching of the external signal or of a signal derived from the latter.

Abstract: Techniques and circuitry are used to more rapidly configuring programmable integrated circuits. Configuration data is input into a programmable integrated circuit in parallel via parallel inputs (705), and this data is also handled internally in parallel. The configuration data will be stored in a data register (722). This data register is segmented into two or more segments, each segment being made up of a serial chain of registers (808). The configuration data is input into the two of more segments of the data registers in parallel. Circuitry is also provided to handle redundancy.

Abstract: In a one-shot, the pulse duration is adjustable through the use of a counter and one or more programmable delay lines in one or more of the feedback loops of the one-shot. The one-shot makes use of at least two flip-flops, and the output of the counter resets the flip-flops.

Abstract: A programmable array logic circuit macrocell using ferromagnetic memory cells. More particularly, the present invention uses a non-volatile ferromagnetic memory cell to temporarily store binary data. It is an advantage of the invention to have the ferromagnetic memory cells or bits to store data even when there is no power provided to the circuitry, thus saving power during operation of the programmable logic circuitry, and ensuring that there is no loss of the data should there be a temporary power shutdown. Additionally, the ferromagnetic cells provide for indefinite number of switching actions on the data without degradation to the capacity to store data therein, thus eliminating “write fatigue”. The invention provides an integrated circuit, comprising a programmable OR array (24), a programmable AND array (28), coupled to the programmable OR array, and a macrocell output circuit (22).

Abstract: Efficient register circuits allow the loading of data values into a memory element using set and reset terminals in addition to loading via the data input terminal. A register circuit includes a memory element and a logical AND gate. A load command input terminal enables the load, and a load value input terminal provides the new value to be loaded. The memory element has set and reset terminals. In one embodiment, the reset function overrides the set function when both terminals provide active signals. The set terminal is coupled to the load command input terminal. The logical AND gate has input terminals coupled to the load command and load value input terminals, and an output terminal coupled to the reset terminal of the memory element. In another embodiment, the set function overrides the reset function, and the signals driving the set and reset terminals are reversed.

Abstract: A temporal delay circuit for synchronizing a source synchronous input with a local clock is provided. The source synchronous input comprises a data input and a source synchronous clock. The temporal delay circuit includes a temporal delay queue, a write pointer arranged to write the data input to the temporal delay queue based on the source synchronous clock, and a read pointer synchronized with the local clock and arranged to read from the temporal delay queue according to a desired delay.

Abstract: The present invention provides a circuit and a method for high speed prescaler circuits which utilize pull-down transistors in the critical feedback path. This invention contains a high speed CMOS dual modulus prescaler circuit made up of data or D-flip flops connected serially where the flip-flop positive output Q of stage N is connected to the D-input of the N+1 flip-flop stage. It is also made up of a pull-down field effect transistor. The invention has a clock input which has a frequency known as a circuit input frequency, Fin. The output of this prescaler circuit has an output frequency, Fout. The frequency division which results from this prescaler circuit is a divide by [2 to the power (n+2)] minus 1 if a mode signal equals 1 as opposed to a divide by [2 to the power (n+2)] counter, which results when the mode signal is low.

Abstract: A programmable I/O element for an I/O terminal of a logic array is suitable for operating according to high speed I/O modes such as double data rate and zero bus turnaround. The I/O element may include an input block with two registers for registering input signals from the terminal upon alternate clock edges. In addition or alternatively, it may include an output block with two registers that separately register output signals from the array on the same clock edge and a multiplexer that alternately outputs those signals. For bidirectional terminals, the multiplexer output is connectable to the I/O terminal via an output buffer, and an output enable block provides an enable signal to a gating input of the output buffer. Programmable delays may be included in the input, output, and output enable paths, in particular to provide a slower turn-on time than turn-off time for the output buffer.

Abstract: A configurable logic block for a programmable logic device includes a storage element having a latch clocked by a write strobe pulse. The storage element uses a write strobe signal and, optionally, a hold signal already present in the CLB. In one embodiment, the CLB includes a function generator, a write strobe generator providing hold and write strobe signals to the function generator, and a storage element driven by the function generator output signal and by the hold and write strobe signals from the write strobe generator. Because the CLB already includes a write strobe generator, it is not necessary to design additional logic to avoid race conditions in the storage element.

Abstract: An additional bit is used in a binary register for detecting register contents in timing and counting applications. A predetermined timing or counting event occurs when the additional bit changes logical states. In one implementation, an additional bit is provided in the most significant bit (MSB) position in a binary register, and is initially set to a logical zero state. When the values in the binary register decrement to zero, the additional (MSB) bit changes logic states to a logical one state, when the zero value in the binary register is decremented in the next clock cycle. A determination is consequently made that the binary register has reached zero.

Abstract: A scan flip-flop circuit achieving higher operation speed, lower power consumption, and a simplified selector section, an array of the scan flip-flop circuits, and an integrated circuit device having therein the array are provided. In a scan flip-flop circuit, an output terminal is provided in addition to an output terminal. One of the output terminals is used for a logic circuit and the other output terminal is used for a scan flip-flop circuit of the next stage. At the output terminal for the scan flip-flop circuit 1 of the next stage, an output is fixed in a normal operation, thereby achieving higher operation speed in the normal operation and lower power consumption. A selector section can employ a relatively simple OR-AND-INVERTER structure.

Abstract: An apparatus for obtaining valid values during a built-in self-testing of logic (“LBIST”) is disclosed. The apparatus includes a first multiplexer, a second multiplexer and a 1-hot init circuit. The 1-hot init circuit includes a scan register, a first inverter, a third multiplexer, a second inverter, and a fourth multiplexer. The scan register includes a plurality of state elements. The first multiplexer is coupled to receive a random data signal and an output of the 1-hot init circuit. Within the 1-hot init circuit, a next to last and a last state element of the scan register is coupled to the inverters and the third and fourth multiplexers, respectively. The first inverter is also coupled to the third multiplexer and the second inverter is coupled to the fourth multiplexer. The output of the fourth multiplexer is coupled to the input of the second multiplexer. Also coupled to the input of the second multiplexer is an input for the random data signal.

Abstract: An electronic circuit containing one or more digital synchronous sequential logic blocks at least one of which is either selected or deselected during operation. The electronic circuit includes an improved clock distribution scheme that reduces power consumption, comprising identifying means for determining the select/deselect state of each said deselectable synchronous sequential logic block, coupled to disabling means for disabling the clock input to each deselected synchronous sequential logic block.

Abstract: A gate array in accordance with the invention includes a matrix of function blocks capable of being configured to implement combinational, sequential, and memory modes of operation, as well as providing tri-state drivers and buffers in useful numbers. The function block includes a logic circuit with a first bit storage unit, which is selectively configurable to behave as combinational logic or to store a first bit, and a second bit storage unit, which is also selectively configurable to behave as combinational logic or to store a second bit. The matrix of function blocks in accordance with the invention is also useful to properly distribute clocks throughout the gate array.

Abstract: A programmable logic device may include a programmable interconnect structure and a plurality of configurable logic elements including data latches interconnected by the interconnect structure. At least one of the configurable logic elements may be configurable as both a shift register and a lookup table. Also, the shift register may be enabled to operate as a bi-directional shift register by the inclusion of a first circuit for configuring the data latches either as series-connected inverters during a shift operation or as data latches after each shift operation. A second circuit for selecting a direction of shifting may also be included, as well as a third circuit for supplying data to the input of the shift register as determined by the direction of shifting.

Abstract: A semiconductor integrated circuit technology that does not invite the drop of &agr;-ray resistance of flip-flop circuits even when devices are miniaturized. A data hold circuit according to this semiconductor integrated circuit technology includes at least three flip-flop circuits using the same signal as an input, and a majority logic circuit for outputting a signal in accordance with a logic value of the majority of the output of these flip-flop circuits.

Abstract: A novel architecture for a multi-scale programmable logic array (MSA) to be used in the design of complex digital systems allows digital logic to be programmed using both small-scale blocks (also called gate level blocks) as well as medium scale blocks (also called Register Transfer Level or RTL blocks). The MSA concept is based on a bit sliceable Arithmetic Logic Unit (ALU). Each bit-slice may be programmed to perform a basic Boolean logic operation or may be programmed to contribute to higher-level functions that are further programmed by an ALU controller circuit. The ALU controller level in this new approach also allows the primitive logic operations computed at the bit-slice level to be combined to perform complex random logic operations. The data shifting capability of this new programmable logic architecture reduces the complexity of the programmable routing needed to implement shift operations including multiplier arrays.

Abstract: An integrated circuit is characterized in that circuit parts contained therein are connected to one another via an interface containing at least one scan register chain. The at least one scan register chain is configured such that data can be input into the scan register chain either via the output terminals of one of the circuit parts or via the input and/or output terminals of the integrated circuit. In addition, data can be output from the scan register chain either at the input terminals of one of the circuit parts or at the input and/or output terminals of the integrated circuit.

Abstract: A flexible and reliable state machine and a semiconductor device using the state machine are provided. A state machine includes a memory circuit (1), a comparator circuit (2), an analyzer circuit (3) and an arithmetic circuit (4). The memory circuit (1) receives and holds data (5-1a) indicative of the next state, and outputs it as data (5-1b) indicative of present state. The comparator circuit (2) compares the date (5-2a) indicative of the present or next state and generates a state flag (6-2b). The analyzer circuit (3) decodes a state flag (6-3a) and generates the control signal (7-3b) for controlling operation of the arithmetic circuit (4). Based on a control signal (7-4a), the arithmetic circuit (4) operates on the data (5-4a) indicative of the present state and generates data (5-4b) indicative of the next state.

Abstract: Methods and apparatus for controlling critical races in sequential circuits so that the there are no conflicts when two or more different data signals exists on shared circuit paths. This enables the design and implementation of sequential circuits having fewer gates than conventional circuit designs of equivalent function that translates into smaller area and power consumption. The control of the critical race is accomplished by adjusting the relative delay of the individual sections of one or more loops.

Abstract: A power-up reference circuit and related method that generates a reference voltage in response to the circuit being powered up. The circuit includes a power-up sensing circuit that generates a set signal, a latch to generate and sustain the reference voltage in response to the set signal, and a reset key decoder to receive an N-bit key and in response thereto generate a reset signal that causes the latch to reset. Upon the circuit being powered up, the power-up sensing circuit generates the set signal which sets the latch to generate the reference voltage. The reference voltage can be used by other circuits to initialize their operating conditions. Once the reference voltage has been used, the N-bit key is generated which causes the decoder to generate the reset signal, which in turn, causes the latch to reset. When the latch is reset, the power-up reference circuit consumes substantially no power.

Abstract: A configuration memory for storing information which is in-system programmable. The programming of the configuration memory may be performed using JTAG (IEEE Standard 1149.1) instructions. Furthermore, the configuration of a programmable logic device using the configuration data in the configuration memory may be initiated with a JTAG instruction. Pull-up resistors are incorporated within the configuration memory package.

Abstract: A system for testing an integrated circuit, and particularly a gate array, is disclosed which includes, prior to coupling the array to form a user-designed circuit, predesigned logic that enables testing of the user-designed circuit. The predesigned logic allows logic blocks in the array to operate in “freeze” mode or to operate in normal mode, where normal mode is defined by the user-designed circuit. When the logic blocks are selected to be frozen, the logic blocks behave as a series of daisy-chained master-slave flip-flops. In normal mode, a logic block can implement combinational, sequential, or other functions and still later be as a master-slave flip-flop. Moreover, each logic block is further equipped for addressable mode control, allowing selected logic blocks to be exercised in isolation once stimulus data is shifted in, simplifying test generation and improving fault coverage.

Abstract: A programmable logic configuration device is disclosed having a configuration memory accessible by a controller of the configuration device and by a second device. Arbitration circuitry is provided for arbitrating access to the configuration memory between the configuration controller and the second device.

Abstract: To conserve power in a circuit where a high-speed signal HSIG controls combinational logic (10), while a low-speed signal LCLK drives a logic/memory circuit (12) that samples the output of the combinational logic, predictive logic state machine (14) generates a clock, P_LCLK, which has an active level preceding the active edge of LCLK by a period sufficient to allow the combinational logic to reach the desired state prior to the active edge of LCLK and, preferably, allows for possible jitter in LCLK. Responsive to P_LCLK, the signal suspend circuitry (16) either passes HSIG or gates off HSIG. Further reductions in power can be accomplished by predicting which portions of the logic/memory circuit (12) will be used, and clocking those portions.

Abstract: A circuit architecture and a method for performing a trimming operation directly on an application board, or after the operation of packaging integrated electronic devices. The circuit architecture includes at least one non-volatile memory unit (3) having non-volatile memory elements (5) and a circuit (17, 19) for modifying the state of the memory elements (5), a first multifunctional input pin (8) whereon a sequence (25) of trimming data is received, a second multifunctional input pin (9) whereon a timing signal of the trimming operations is received, and an additional access pin (7) for switching the circuit architecture operation from a normal mode over to a trimming mode.

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: A queue length arbiter system provides for selecting from a plurality of N queues requiring access to a resource. The system includes: an arbitration circuit; and a plurality of weight circuits each being associated with a corresponding one of the queues, and being operative to store a corresponding weight count value, and also being operative to initialize the corresponding weight count value to a corresponding initial weight value determined based on a length value indicative of a number of data portions enqueued at the corresponding queue at an initial time, and being further operative to decrease the corresponding weight count value in response to a corresponding one of a plurality of grant signals, and also being operative to generate a corresponding one of a plurality of weight count signals, the corresponding weight count signal carrying the corresponding weight count value.

Abstract: An unclocked, digital sequencer circuit having flexibly ordered leading and trailing edges on the output signals. The sequencer circuit of the invention includes a dual-input latch that detects only leading edges on a first input terminal and only trailing edges on a second input terminal. A delay line provides successively delayed input signals. Two delayed input signals are coupled to the first and second input terminals of each of two or more dual-input latches that provide a set of sequencer output signals. The sequence of the output signal edges depends on which delayed input signals are selected to drive each dual-input latch. In one embodiment, the selection of delayed input signals to drive the first and second input terminals of the dual-input latches is programmable. Thus, the sequence of the leading edges on the output signals is programmable, and the sequence of the trailing edges is independently programmable.

Abstract: An unclocked, digital sequencer circuit having flexibly ordered leading and trailing edges on the output signals. The sequencer circuit of the invention includes a dual-input latch that detects only leading edges on a first input terminal and only trailing edges on a second input terminal. A delay line provides successively delayed input signals. Two delayed input signals are coupled to the first and second input terminals of each of two or more dual-input latches that provide a set of sequencer output signals. The sequence of the output signal edges depends on which delayed input signals are selected to drive each dual-input latch. In one embodiment, the selection of delayed input signals to drive the first and second input terminals of the dual-input latches is programmable. Thus, the sequence of the leading edges on the output signals is programmable, and the sequence of the trailing edges is independently programmable.

Abstract: There can be provided a variable function information processor in which a logic module (10) with the further decreased number of transistors used in the logic module constituting the variable function information processor is provided, a function of being able to realize both a combinational logic circuit for-performing a full addition operation of input signals in accordance with a control signal and outputting the sum and a sequential circuit for temporarily holding the input signal to delay the signal and outputting it by the same logic module is provided, and in a semiconductor circuit element group for constituting the combinational logic circuit and the sequential circuit, a common part of the combinational logic circuit and the sequential circuit is used for both the circuits, whereby the number of elements can be further decreased, and the resources of the variable function information processor can be effectively exploited.

Abstract: A system and method for designing a digital circuit. The method includes identifying a single phase digital circuit implementing a desired function and operating at a first rate and determining a number of copies of the single phase digital circuit that are required for the digital circuit. Each copy of the single phase circuit is a phase and operates at a lesser rate wherein the sum of the lesser rates is less than or equal to the first rate. The method includes identifying the state devices within the single phase digital circuit, replacing each state device in the single phase digital circuit with a multiphase state saving device and providing control signals to each multiphase state saving device to control the reading and writing of state information for each phase into and out of a respective multiphase state saving device.

Abstract: A multi-threshold flip-flop circuit having an outside feedback is disclosed. The multi-threshold flip-flop circuit comprises a master latch and a slave latch. Coupled between an output of the slave latch and an input of the master latch, a switchable feedback path is utilized to retain logical values of the slave latch during a sleep mode of the flip-flop circuit.

Abstract: A multi-threshold flip-flop circuit having an outside feedback is disclosed. The multi-threshold flip-flop circuit comprises a master latch and a slave latch. Coupled between an output of the slave latch and an input of the master latch, a switchable feedback path is utilized to retain logical values of the slave latch during a sleep mode of the flip-flop circuit.

Abstract: A fast, space-efficient lookup table (LUT) for programmable logic devices (PLDs) in which the write decoder, read decoder and memory block of the LUT are modified to improve performance while providing a highly efficient layout. Both the write decoder and the read decoder are controlled by LUT input signals, and data signals are transmitted directly to each memory circuit of the memory block (i.e., without passing through the write decoder). The read decoder includes a multiplexing circuit made up of a series of multiplexers that are directly controlled by the input signals received from the interconnect resources of the PLD. In one embodiment, a configurable logic block is provided with a single write decoder that is shared by a first LUT and a second LUT.

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: A data processing system having a user configurable memory controller, one or more block RAMS, and a processor core can be configured in a single field programmable gate array (FPGA). The address depth of the block RAMs and the number of wait states can be selected by a user, and they can be set either prior to configuration of the FPGA or programmed using instructions of the processor core. An algorithm that can optimize the address depth and the number of wait states to achieve a performance level is also disclosed. The present invention can be applied to designs having separate instruction and data sides.

Abstract: The plurality of flip-flops included in a logic circuit are grouped by the clock source, thereby judging a relatively large part of the clock skew. Namely, the relatively large clock skew generates between the scan flip-flop belonging to a certain group connected by the scan path and the scan flip-flop belonging to another group. Specifically, as the last scan flip-flop of each group is connected to the scan flip-flop belonging to another group, the scan flip-flop including the delay circuit is applied to the last scan flip-flop of each group, whereby it is possible to regulate the relatively large clock skew by use of the less number of basic cells by insertion of the buffer.

Abstract: In a data processing system, a circuit and methods for carrying out sequential logic functions are disclosed aimed at overcoming the problems encountered with the standard approach for designing synchronous logic, timed from a single clock source. When propagation delays through logic elements and their interconnections are becoming of the same order of magnitude as the clock period necessary to achieve the required level of performance of a logic function, the distribution of a common timing reference or clock over an entire function is becoming the limiting factor. In a complete departure from the standard approach, logic functions of the invention are capable of supplying their own timing information to their interface thus, self asserting their result and capable of requesting new set of inputs when needed. Therefore, logic functions of the invention are autonomous and do not rely on the distribution of a clock to operate.