Abstract: A programmable logic array integrated circuit device includes a plurality of regions of programmable logic disposed on the device in a two-dimensional array of intersecting rows and columns. Interconnection conductors are associated with each row and column. The interconnection conductors associated with each row include some that extend continuously along the entire length of the row and some that extend continuously along only the left or right half of the row. To increase the flexibility with which the logic regions can be connected to the row and column conductors, adjacent regions are paired and circuitry is provided for allowing the outputs of each pair to be swapped for driving the row and column conductors. Registers in logic regions can still be used for other purposes when not being used to register the main combinatorial outputs of the logic regions. Many other enhanced features are also provided.

Abstract: A programmable logic array integrated circuit has a number of programmable logic modules which are grouped together in a plurality of logic array blocks (“LABs”). The LABs are arranged on the circuit in a two dimensional array. A conductor network is provided for interconnecting any logic module with any other logic module. In addition, adjacent or nearby logic modules are connectable to one another for such special purposes as providing a carry chain between logic modules and/or for connecting two or more modules together to provide more complex logic functions without having to make use of the general interconnection network. Another network of so-called fast or universal conductors is provided for distributing widely used logic signals such as clock and clear signals throughout the circuit. Multiplexers can be used in various ways to reduce the number of programmable interconnections required between signal conductors.

Abstract: Error detection circuitry is provided on a programmable logic resource. Programmable logic resource configuration data is loaded into a cyclic redundancy check (CRC) module where a checksum calculation may be performed. In one embodiment, the checksum may be compared to an expected value, which is a precomputed checksum on data prior to being programmed into or while data is being programmed into a programmable logic resource. In another embodiment, the expected value may be included in the checksum calculation. An output indicating whether an error is detected may be generated depending on the relationship between the checksum and the expected value, or on the value of the checksum. This output may be sent to an output pin that is accessible by user logic.

Abstract: A programmable logic array integrated circuit device includes a plurality of regions of programmable logic disposed on the device in a two-dimensional array of intersecting rows and columns. Interconnection conductors are associated with each row and column. The interconnection conductors associated with each row include some that extend continuously along the entire length of the row and some that extend continuously along only the left or right half of the row. To increase the flexibility with which the logic regions can be connected to the row and column conductors, adjacent regions are paired and circuitry is provided for allowing the outputs of each pair to be swapped for driving the row and column conductors. Registers in logic regions can still be used for other purposes when not being used to register the main combinatorial outputs of the logic regions. Many other enhanced features are also provided.

Abstract: Embedding a logic analyzer in a programmable logic device allows signals to be captured both before and after a trigger condition (breakpoint). A logic analyzer embedded within a PLD captures and stores logic signals. It unloads these signals for viewing on a computer. Using an electronic design automation (EDA) software tool running on a computer system, an engineer specifies signals of the PLD to be monitored, a breakpoint, total number of samples to be stored, number of samples to be captured after the breakpoint occurs, and a system clock signal. The EDA tool automatically inserts the logic analyzer into the electronic design of the PLD which is compiled and downloaded to configure the PLD. Using an interface connected between the PLD and the computer, the EDA tool commands the embedded logic analyzer to run. Signals are stored continuously while running in a ring buffer RAM memory. Once the breakpoint occurs, more samples are captured if desired, in addition to those signals captured before breakpoint.

Abstract: In a programmable logic device, input/output circuits are grouped into blocks. Each block includes input/output circuits capable of handling a plurality of logic signalling schemes, which may require different supply voltages and reference voltages. Each block also has its own power supply bus. In this way, the different blocks can be provided with different supply and reference voltages, so that different blocks can be used for different logic signalling schemes, thereby allowing more than one such scheme to be used simultaneously on a single device. A single block could also be implemented with more than one scheme active, as long as all of the schemes in use in the block have the same power supply requirements and—to the extent that each such scheme requires a reference voltage—the same reference voltage requirements.

Abstract: Embedding a logic analyzer in a programmable logic device allows signals to be captured both before and after a trigger condition (breakpoint). A logic analyzer embedded within a PLD captures and stores logic signals. It unloads these signals for viewing on a computer. Using an electronic design automation (EDA) software tool running on a computer system, an engineer specifies signals of the PLD to be monitored, a breakpoint, total number of samples to be stored, number of samples to be captured after the breakpoint occurs, and a system clock signal. The EDA tool automatically inserts the logic analyzer into the electronic design of the PLD which is compiled and downloaded to configure the PLD. Using an interface connected between the PLD and the computer, the EDA tool commands the embedded logic analyzer to run. Signals are stored continuously while running in a ring buffer RAM memory. Once the breakpoint occurs, more samples are captured if desired, in addition to those signals captured before breakpoint.

Abstract: A programmable logic array integrated circuit device includes a plurality of regions of programmable logic disposed on the device in a two-dimensional array of intersecting rows and columns. Interconnection conductors are associated with each row and column. The interconnection conductors associated with each row include some that extend continuously along the entire length of the row and some that extend continuously along only the left or right half of the row. To increase the flexibility with which the logic regions can be connected to the row and column conductors, adjacent regions are paired and circuitry is provided for allowing the outputs of each pair to be swapped for driving the row and column conductors. Registers in logic regions can still be used for other purposes when not being used to register the main combinatorial outputs of the logic regions. Many other enhanced features are also provided.

Abstract: A dual-port programmable logic device memory array is provided. Selectable-size data words may be written to and read from the array concurrently. Data is written into the array using write column decoder and data selection logic. The size of the data words handled by the write column decoder and data selection logic is controlled by mode select signals. Data is read from the array using read column decoder and data selection logic. The size of the data words handled by the read column decoder and data selection logic is also controlled by mode select signals. The write column decoder and data selection logic may be used to write data into the memory array at one selected location at the same time that the read column decoder and data selection logic is used to read data from the array at another selected location. A write row address decoder and a read row address decoder are used to independently address individual rows of memory cells in the memory array during writing and reading, respectively.

Abstract: Programmable logic array devices are programmed from programming devices in networks that facilitate programming any number of such logic devices with programs of any size or complexity. The source of programming data and control may be a microprocessor or one or more serial EPROMs, one EPROM being equipped with a clock circuit. Several parallel data streams may be used to speed up the programming operation. A clock circuit with a programmably variable speed may be provided to facilitate programming logic devices with different speed characteristics. The programming protocol may include an acknowledgment from the logic device(s) to the programming data source after each programming data transmission so that the source can automatically transmit programming data at the speed at which the logic device is able to accept that data.

Abstract: In a programmable logic device, input/output circuits are grouped into blocks. Each block includes input/output circuits capable of handling a plurality of logic signalling schemes, which may require different supply voltages and reference voltages. Each block also has its own power supply bus. In this way, the different blocks can be provided with different supply and reference voltages, so that different blocks can be used for different logic signalling schemes, thereby allowing more than one such scheme to be used simultaneously on a single device. A single block could also be implemented with more than one scheme active, as long as all of the schemes in use in the block have the same power supply requirements and—to the extent that each such scheme requires a reference voltage—the same reference voltage requirements.

Abstract: A programmable logic array integrated circuit device has a plurality of regions of programmable logic disposed on the device in a two-dimensional array of intersecting rows and columns of regions. The output signals of several regions share a group of drivers for applying region output signals to interconnection conductors that convey signals between regions. This conserves driver resources and increases signal routing flexibility. Various approaches can be used for configuring the interconnection conductors to also conserve interconnection conductor resources. Logic regions may be used to directly drive specific input/output cells, thereby simplifying signal routing to the I/O cells and also possibly simplifying the structure of the I/O cells (e.g., by allowing certain I/O cell functions to be performed in the associated logic region).

Abstract: The invention relates to an integrated circuit that can be configured to operate as a content addressable memory. The integrated circuit includes a first functional block that stores at least one keyword dataword which is associated with a group of associated data words. The integrated circuit also includes a second functional block that stores the group of associated datawords. The second functional block is connected to the first functional block in such a way that if a request dataword received at the first functional block matches at least one keyword dataword stored therein, then an associated result dataword included in the group of associated data words stored in the second functional block is output by the second functional block. Typically, the integrated circuit chip is a complex programmable logic device architecture (CPLD).

Abstract: In order to facilitate the performance of multiplications in programmable logic devices, individual logic modules of such devices are constructed so that one logic module can perform (at least) both one place of binary multiplication and one place of full binary addition. This makes it possible to reduce the number of logic modules that are required to perform a multiplication. It also reduces the number of inter-module connections employed in a multiplication, thereby tending to decrease the time required to perform a multiplication.

Abstract: Embedding a logic analyzer in a programmable logic device allows signals to be captured both before and after a trigger condition (breakpoint). A logic analyzer embedded within a PLD captures and stores logic signals. It unloads these signals for viewing on a computer. Using an electronic design automation (EDA) software tool running on a computer system, an engineer specifies signals of the PLD to be monitored, a breakpoint, total number of samples to be stored, number of samples to be captured after the breakpoint occurs, and a system clock signal. The EDA tool automatically inserts the logic analyzer into the electronic design of the PLD which is compiled and downloaded to configure the PLD. Using an interface connected between the PLD and the computer, the EDA tool commands the embedded logic analyzer to run. Signals are stored continuously while running in a ring buffer RAM memory. Once the breakpoint occurs, more samples are captured if desired, in addition to those signals captured before breakpoint.

Abstract: In a programmable logic device, input/output circuits are grouped into blocks. Each block includes input/output circuits capable of handling a plurality of logic signalling schemes, which may require different supply voltages and reference voltages. Each block also has its own power supply bus. In this way, the different blocks can be provided with different supply and reference voltages, so that different blocks can be used for different logic signalling schemes, thereby allowing more than one such scheme to be used simultaneously on a single device. A single block could also be implemented with more than one scheme active, as long as all of the schemes in use in the block have the same power supply requirements and—to the extent that each such scheme requires a reference voltage—the same reference voltage requirements.

Abstract: A programmable logic array integrated circuit device has a plurality of regions of programmable logic disposed on the device in a two-dimensional array of intersecting rows and columns of regions. The output signals of several regions share a group of drivers for applying region output signals to interconnection conductors that convey signals between regions. This conserves driver resources and increases signal routing flexibility. Various approaches can be used for configuring the interconnection conductors to also conserve interconnection conductor resources. Logic regions may be used to directly drive specific input/output cells, thereby simplifying signal routing to the I/O cells and also possibly simplifying the structure of the I/O cells (e.g., by allowing certain I/O cell functions to be performed in the associated logic region).

Abstract: Embedding a logic analyzer in a programmable logic device allows signals to be captured both before and after a trigger condition (breakpoint). A logic analyzer embedded within a PLD captures and stores logic signals. It unloads these signals for viewing on a computer. Using an electronic design automation (EDA) software tool running on a computer system, an engineer specifies signals of the PLD to be monitored, a breakpoint, total number of samples to be stored, number of samples to be captured after the breakpoint occurs, and a system clock signal. The EDA tool automatically inserts the logic analyzer into the electronic design of the PLD which is compiled and downloaded to configure the PLD. Using an interface connected between the PLD and the computer, the EDA tool commands the embedded logic analyzer to run. Signals are stored continuously while running in a ring buffer RAM memory. Once the breakpoint occurs, more samples are captured if desired, in addition to those signals captured before breakpoint.

Abstract: A dual-port programmable logic device memory array is provided. Selectable-size data words may be written to and read from the array concurrently. Data is written into the array using write column decoder and data selection logic. The size of the data words handled by the write column decoder and data selection logic is controlled by mode select signals. Data is read from the array using read column decoder and data selection logic. The size of the data words handled by the read column decoder and data selection logic is also controlled by mode select signals. The write column decoder and data selection logic may be used to write data into the memory array at one selected location at the same time that the read column decoder and data selection logic is used to read data from the array at another selected location. A write row address decoder and a read row address decoder are used to independently address individual rows of memory cells in the memory array during writing and reading, respectively.

Abstract: A programmable logic integrated circuit device has several features which help it perform according to the PCI Special Interest Group's Peripheral Component Interface (“PCI”) signaling protocol. Regions of programmable logic within the device are closely coupled to the data signal output pins and clock signal input pins such that delay between application of a clock signal to the device and output of a data signal from the device is within PCI signal standards for delay. The device also includes output circuitry that can be configured to selectively invert signals to output enable and data input enable terminals of the output circuitry.