Abstract: A semiconductor die includes at least one flexible interface block. The flexible interface block includes at least one interconnect, and at least one buffer coupled to the at least one interconnect. The flexible interface block further includes a routing interface coupled to circuitry integrated in the semiconductor die, and a controller coupled to provide communication between the routing interface and the at least one buffer.

Abstract: A semiconductor die includes at least one flexible interface block. The flexible interface block includes at least one interconnect, and at least one buffer coupled to the at least one interconnect. The flexible interface block further includes a routing interface coupled to circuitry integrated in the semiconductor die, and a controller coupled to provide communication between the routing interface and the at least one buffer.

Abstract: A semiconductor die includes at least one flexible interface block. The flexible interface block includes at least one interconnect, and at least one buffer coupled to the at least one interconnect. The flexible interface block further includes a routing interface coupled to circuitry integrated in the semiconductor die, and a controller coupled to provide communication between the routing interface and the at least one buffer.

Abstract: A semiconductor die includes at least one flexible interface block. The flexible interface block includes at least one interconnect, and at least one buffer coupled to the at least one interconnect. The flexible interface block further includes a routing interface coupled to circuitry integrated in the semiconductor die, and a controller coupled to provide communication between the routing interface and the at least one buffer.

Abstract: A semiconductor die includes at least one flexible interface block. The flexible interface block includes at least one interconnect, and at least one buffer coupled to the at least one interconnect. The flexible interface block further includes a routing interface coupled to circuitry integrated in the semiconductor die, and a controller coupled to provide communication between the routing interface and the at least one buffer.

Abstract: A semiconductor die includes at least one flexible interface block. The flexible interface block includes at least one interconnect, and at least one buffer coupled to the at least one interconnect. The flexible interface block further includes a routing interface coupled to circuitry integrated in the semiconductor die, and a controller coupled to provide communication between the routing interface and the at least one buffer.

Abstract: A semiconductor die includes at least one flexible interface block. The flexible interface block includes at least one interconnect, and at least one buffer coupled to the at least one interconnect. The flexible interface block further includes a routing interface coupled to circuitry integrated in the semiconductor die, and a controller coupled to provide communication between the routing interface and the at least one buffer.

Abstract: A method for determining clock uncertainties is provided. The method includes identifying clock transfer types between registers from an integrated circuit design and identifying contributors to the clock uncertainties for each of the clock transfers. The jitter associated with each identified contributor is calculated for both set-up time and hold time. This calculated jitter is incorporated into a slack calculation to determine whether timing constraints are met for a circuit design.

Abstract: Multiplier-accumulator circuitry includes circuitry for forming a plurality of partial products of multiplier and multiplicand inputs, carry-save adder circuitry for adding together the partial products and another input to produce intermediate sum and carry outputs, final adder circuitry for adding together the intermediate sum and carry outputs to produce a final output, and feedback circuitry for applying the final output (typically after some delay, e.g., due to registration of the final output) to the carry-save adder circuitry as said another input. The above circuitry may be implemented in so-called “hard IP” (intellectual property) of a field-programmable gate array (“FPGA”) integrated circuit device. If desired, any overflow from the accumulation performed by the above circuitry may be accumulated in “soft” accumulator-overflow circuitry that is implemented in the general-purpose programmable logic of the FPGA.

Abstract: Dual port memory array circuitry is provided that includes bit line voltage clamping circuitry. The clamping circuitry contains control transistors that are used to enable and disable the clamping circuitry. The clamping circuitry also contains voltage regulator transistors and feedback paths. When a write operation is performed on one port of the dual port memory array while a read operation is being performed on the other port of the dual port memory array, the bit line voltage clamping circuitry prevents the voltages on the read port bit lines from dropping too low. This allows the write operation to be performed rapidly, even if the memory cell being written to has been adversely affected by variations due to process, voltage, and temperature.

Abstract: Method and apparatus for configuring a programmable logic device to operate at a plurality of clock frequencies comprising configurable programmable self-timed delay circuits and associated configuration software. The configurable IC clock frequencies increase device performance and manufacturing yield.

Abstract: Dual port memory array circuitry is provided that includes bit line voltage clamping circuitry. The clamping circuitry contains control transistors that are used to enable and disable the clamping circuitry. The clamping circuitry also contains voltage regulator transistors and feedback paths. When a write operation is performed on one port of the dual port memory array while a read operation is being performed on the other port of the dual port memory array, the bit line voltage clamping circuitry prevents the voltages on the read port bit lines from dropping too low. This allows the write operation to be performed rapidly, even if the memory cell being written to has been adversely affected by variations due to process, voltage, and temperature.

Abstract: A first-in, first-out (“FIFO”) memory system embedded in a programmable logic device has an embedded FIFO memory array coupled to an output register. If the embedded FIFO memory is empty, the first word written to the FIFO memory system is pre-fetched to the output register. A first-word detection circuit asserts a DATA VALID signal if the first word is available to be read from the output register when READ ENABLE is asserted. In an alternative embodiment, the first word is pre-fetched to the output of the output register and is available to be read before READ ENABLE is asserted.

Abstract: Programmable logic devices (PLDs) including self-repairing RAM circuits, and methods of automatically replacing defective columns in RAM arrays. A RAM circuit including redundant columns is tested during the PLD configuration sequence using a built in self test (BIST) procedure. If a defective column is detected, an error flag is stored in an associated volatile memory circuit. After the BIST procedure is complete, the PLD configuration process continues. The presence of the error flag causes the configuration data to bypass the defective column and to be passed directly into a replacement column. The configuration process continues until the remainder of the circuit is configured, including the redundant column. In other embodiments, the BIST procedure is initiated independently from the PLD configuration process. When a defective column is detected, user operation resumes with data being shunted from the defective column to a redundant column in a fashion transparent to the user.

Abstract: An integrated circuit having an embedded first-in, first-out (“FIFO”) memory system uses an embedded block random access memory (“BRAM”). Counters operate in both the read and write clock domains. A binary adder adds a first selected offset value and to a first pointer address, and the sum is converted to a first gray code value. The first gray code value is compared to a second gray code value that represents a second pointer address. If the first gray code value equals the second gray code value, the output of the comparator is provided to a logic block that produces a status flag (e.g. ALMOST FULL or ALMOST EMPTY) in the correct clock domain.

Abstract: A buffer memory status detection circuit has a binary logic gate (e.g. an OR gate) coupled to a comparator output signal that is asserted when a sum of a first address pointer of a FIFO memory array plus a first offset equals a second address pointer, and to a reset signal. Binary logic provides a binary output (i.e. “0” or “1”) in a first clock domain to two synchronization registers in series that convert the output to a second clock domain. An optional pipeline register improves timing of the output in the second clock domain, and is particularly desirable for use with high-speed clocks.

Abstract: A system for gray-code counting in an integrated circuit such as a programmable logic device uses a binary adder coupled to a binary counter output and to a selected binary offset value. The binary adder provides a binary sum that is converted to a gray code value by a binary-to-gray converter. The gray code value represents the binary sum output.

Abstract: An integrated circuit having an embedded first-in, first-out (“FIFO”) memory system uses an embedded block random access memory (“BRAM”). Counters operate in both the read and write clock domains. A binary adder adds a first selected offset value and to a first pointer address, and the sum is converted to a first gray code value. The first gray code value is compared to a second gray code value that represents a second pointer address. If the first gray code value equals the second gray code value, the output of the comparator is provided to a logic block that produces a status flag (e.g. ALMOST FULL or ALMOST EMPTY) in the correct clock domain.

Abstract: A programmable logic device has embedded random access memory (“RAM”) that can function equally well in either single-port or dual-port operation. The RAM is dual-port RAM whose read address inputs and write address inputs are both connected to a conductor bus via two different sparsely populated programmable interconnection resources. The programmable interconnection resources are arranged so that each pair of corresponding read address and write address inputs can be connected to at least one conductor in common on the conductor bus, allowing the RAM to be configured to mimic a single-port RAM as read address signals and write address signals originating at remote components of the programmable logic device “think” they are being directed to the same address inputs.

Abstract: Dual port memory array circuitry is provided that includes bit line voltage clamping circuitry. The clamping circuitry contains control transistors that are used to enable and disable the clamping circuitry. The clamping circuitry also contains voltage regulator transistors and feedback paths. When a write operation is performed on one port of the dual port memory array while a read operation is being performed on the other port of the dual port memory array, the bit line voltage clamping circuitry prevents the voltages on the read port bit lines from dropping too low. This allows the write operation to be performed rapidly, even if the memory cell being written to has been adversely affected by variations due to process, voltage, and temperature.