Abstract: Logic signal routability in programmable logic array integrated circuit devices is improved by selecting the possible interconnections between various resources on the device so that various constraints or goals are satisfied. Improving routability in this way tends to reduce instances in which desired interconnections are blocked by other connections that have already been made.

Abstract: A sequence generator for generating multiple-pattern sequences utilizing an inverting non-linear autonomous machine is disclosed. The generation of the sequence is based on the interdependency relationship between the bits of the deterministic patterns in the sequences to be generated. The autonomous machine comprises a number of flip-flop cascades each containing a number of flip-flops. The flip-flops in each of the cascades are connected in a way that the output of one flip-flop is connected to the input of the next flip-flop in each cascade. The autonomous machine further comprises a number of XOR gates each feeding its output to the input of a corresponding one of the cascades of flip-flops. The autonomous machine further comprises a switch device that includes a number of switches for receiving the output of each of the flip-flops in the cascades as feedbacks for outputting to the inputs of the XOR gates.

Abstract: An integrated circuit incorporating programmable pullup and pulldown devices into each input/output (I/O) pad is described. Each I/O pad may be individually programmed to include a pullup or pulldown function. Pullup and pulldown resistors may be removed from a system employing the present integrated circuit. Programming of the I/O pads may be accomplished in a number of ways. Following the deassertion of a reset signal, high impedance states may be transferred into a shift data storage within the integrated circuit. Once the states are received, they are shifted to the respective I/O pads through a serial chain connection of the pullup and pulldown devices within each I/O pad. The states are then maintained by each pullup and pulldown device until a subsequent reprogramming. Software programs may also reprogram the pullup and pulldown states by storing appropriate values into the shift data storage. The program then sets an appropriate value into a status register included within the integrated circuit.

Abstract: A programmable drive strength buffer includes a control signal used to enable/disable an output drive transistor slew rate control circuit, and a current drive strength control bits which are used to select weak, medium or strong current drive capability over an ISA bus with loads varying from 60 pF to 240 pF for a supply voltage of 5.0 or 3.3 volts.

Abstract: In a microcircuit device such as a memory chip, where a bank of fuse-controlled latch pulse routing-circuits are used to program redundant circuits or other programming options with every memory cycle or multiple thereof, the amount of current drawn by every fuse-control circuit is reduced by controlling each bank of circuits with a bank-enabling, fuse-programmed circuit between the latch pulse source and the bank of fuse-controlled programing circuits, and by adding a second fuse into each programming circuit; whereby, the bank of programming circuits can be enabled by alternately blowing one of two fuses in the bank-enabling circuit, and each programing logic can be set by alternately blowing one of its pair of fuses, thus cutting off any current path through the programming circuit regardless of the programming state of the circuit.

Abstract: This device in which the network includes a transmission cable (4) fitted with a pair of conductors (2, 3), is characterized in that each conductor (2, 3) of the cable is linked at each of its ends to a terminal of a resistor (9, 10) whose value is equal to half the value of the characteristic impedance of the cable (4) and the other terminal of which is linked to a voltage source (11, 12).

Abstract: A modular bus permitting single or double termination is described. The bus includes a terminated motherboard data net for communicating data signals between a master and one or more motherboard devices. A socket is used for coupling the data signals between the motherboard data net and a terminated module data net of a removable module. The module data net communicates the data signals between the master and one or more module devices. The data signal swing and level of reflection of the data signals are substantially independent of the presence of the module.

Abstract: An integrated circuit includes a terminal which is accessible externally of the integrated circuit, and circuitry (LOB) coupled to said terminal and operable to latch at said terminal a signal applied to said terminal by a source (ICT) external to said integrated circuit.

Abstract: A metal interconnect line for conducting a first signal from a first line segment of a field programmable gate array to a second line segment. The metal interconnect line substantially spans across the width of the field programmable gate array and has at least one bi-directional buffer that separates the metal interconnect line into a plurality of independent segments. Each of these segments can conduct signals independently from the other segments when the bidirectional buffer is in a tristate mode. Alternatively, a single signal may be routed through the entire length of the metal line in one or the other direction, and repowered along the way. One or more of the bi-directional buffers are used to actively drive the signal(s) onto later segments of the metal interconnect line.

Abstract: A programmable ASIC architecture allows the size of programming transistors to be reduced along with other parts of the device as advances in processing technology are made. Programming enable circuits are used to allow a programming address shift register having fewer bits to be used in the programming of antifuses. Methods of simultaneously programming multiple corresponding antifuses to speed ASIC programming are disclosed. Aspects of the architecture allow output protection for digital logic elements in modules to be eliminated, some testing transistors to be eliminated, the sizes of other testing transistors to be reduced, capacitances on interconnect wire segments to be reduced, some programming transistors to be eliminated, and the sizes of other programming transistors to be reduced.

Abstract: An input/output circuit for increasing immunity to voltage spikes from voltage supplies is provided. The circuit includes a first pair of transistors each having their drains connected to an output terminal and their sources connected to voltage supplies. A mechanism is connected to electrically separated voltage supplies to alternately turn on one of the first pair of transistors responsive to an input signal. A transistor is utilized to provide feedback to limit the rise in a ground voltage supply as occurs during ground bounce.

Abstract: A circuit (51) for converting a pair of precharged dynamic logic signals into a static logic signal includes a first input (61) to receive one of said dynamic logic signals, a second input (67) to receive the other of said dynamic logic signals, and an output (Qout). A first signal path from said first input to said output includes only two logic gates (63,69), and a second signal path from said second input to said output includes only one logic gate (69).

Abstract: A programmable logic device (PLD) for implementing pipelined designs is described. A pipeline array of registers and function generators, comprises registers and function generators arranged along a line in a first direction, the first direction being a direction of propagation of data signals, and registers and function generators arranged along a line in a second direction, the second direction being a direction of propagation of carry signals and control signals. Each of said function generators is operatively connected by routing resources to at least two of the registers within the pipeline array. A synchronization ring of the PLD comprises shift registers, each of the shift registers being programmable such that its bit length can be adjusted from one bit to a predefined maximum number of bits. The synchronization ring surrounds and is operatively connected by routing resources to the pipeline array.

Abstract: A multiplexing arrangement. The multiplexing arrangement comprises a set of data inputs wherein a first multiplexer is coupled to a first subset of the set of data inputs and a second multiplexer is coupled to a second subset of the set of data inputs. Only one of the first and second multiplexers is selected to pass one of the set of data inputs at any given time. A logic gate is coupled to the first and second data outputs, and the logic gate synthesizes an output signal for the multiplexing arrangement in response to values output by the first and second multiplexers such that the multiplexing arrangement operates as a single multiplexer. According to one embodiment, the multiplexer that is not selected to pass data has its output biased to a known state.

Abstract: A domino logic circuit includes an evaluation circuit for receiving input signals and performing a logic operation on the input signals, a passgate circuit for controlling the transmission of signals to an output circuit and a feedback latch circuit for holding the output of the evaluation circuit for a predetermined portion of a clock cycle. The output circuit may also include a pair of control transistors to allow the output latching circuit to be turned off during the evaluate portion of the clock cycle thus improving the speed of the domino logic circuit. During the first half of the reset portion of each cycle, the output latching circuit is active and allows the circuit to retain its output state. During the time the passgates are turned off, the evaluate circuit is disconnected and may begin resetting. During the second half of the reset portion of the clocking signal, the passgates open, which allows the output stage to be reset.

Abstract: A programmable logic device (PLD) comprises a plurality of configurable logic blocks (CLBs), an interconnect structure for interconnecting the CLBs, and a plurality of programmable logic elements for configuring the CLBs and the interconnect structure. Each CLB includes a combinational element and a sequential logic element, wherein at least one programmable logic element includes a plurality of memory cells for configuring the combinational element and at least one programmable logic element includes a plurality of memory cells for configuring the sequential logic element. A micro register, which stores a plurality of intermediate states of one CLB or interconnect structure, is located at the output of a CLB, the input of a CLB, or elsewhere in the interconnect structure. The PLD includes means for disabling access to at least one of said plurality of memory elements. In one embodiment, the memory cells are RAM cells, whereas in other embodiments the memory cells are ROM cells, or a combination thereof.

Abstract: In each of multiple logic cells of a Programmable Gate Array ("PGA"), a programing array is provided having multiple programming words therein. Each of the programming words is engagable to control the configuration of the logic cell. The programming words are selectively engaged such that multiple functions are performed by the logic cell within the PGA. As a result, a PGA with a number of virtual logic cells in excess of actual physical logic cells is provided. The PGA therefore has the capability to emulate a PGA with a larger number of logic cells than it physically has.

Abstract: An integrated circuit includes a plurality of signal lines, a plurality of pull transistors connected between the signal lines respectively and an electrical potential, and an IDDQ test control for turning on the pull transistors for normal operation, and for turning off the pull transistors for IDDQ testing. The IDDQ test control includes a test signal generator for generating an IDDQ test control signal that turns off the pull transistors, and an IDDQ test signal line that is connected to the test signal generator and to the pull transistors. The pull transistors are designed within a periphery of the circuit, and the IDDQ test signal line forms a ring. The test signal generator includes an external pin, a special buffer, or a boundary scan system including a chain of boundary scan cells and a test access port controller. The test control signal can be generated by one of the boundary scan cells, or by the test access port controller.

Abstract: A zero-stopping incrementer operates on the recognition that half of all digital values that require incrementing will be even numbers; that is, the least significant bit (LSB) is a binary "0". Incrementing such a number merely requires changing the LSB from a binary "0" to a binary "1". For odd numbers (i.e., those where the LSB is a binary "1"), the zero-stopping incrementer searches for the first binary "0" beginning with the LSB. Once found, that binary "0" is changed to a binary "1" and all the binary "1s" preceding it are changed to binary "0s". No change is required to the higher order bits following the first binary "0". This operation is very fast, the worst case being the case when all the binary bits of the number to be incremented are "1s". Nevertheless, the process is significantly increased, especially for 64-bit numbers which are processed by modern superscalar microprocessors.

Abstract: A configurable logic block (CLB) in the dual port mode uses one address to write the same information in a first RAM and a second RAM. The input signals provided to the second function generator can be used to read, independently from and even asynchronously with, the write operation, thereby dramatically increasing the speed of applications using the two sets of RAM. A CLB in the synchronous mode latches the appropriate address and data signals, and generates a strobed write enable signal. The strobed signal is self-timed, i.e. the write operation is fully automatic, thereby ensuring that a write operation occurs within one clock cycle.