Abstract: Each output signal of programmable logic circuitry is made programmably available to drive one or more of a plurality of tri-statable input/output pins of the circuitry. Each output signal is also made programmably available to provide the output enable signal for one or more of a multiplicity of those input/output pins. The above-mentioned plurality and multiplicity associated with each output signal may include the same or different input/output pins. Output signals may therefore be routed to the input/output pins with greater flexibility, and output enable signal options are also greatly increased.

Abstract: Partitioning of a circuit design to facilitate economical implementation of that circuit in a physical circuit that is made up of two or more physical subcircuits is improved by starting with two different, conventionally produced partitions of the design and combining selected features of those two starting partitions to produce a final partition that is better than either of the starting partitions.

Abstract: A programmable logic device (10) has a number of programmable logic elements (LEs) (12) which are grouped together in a plurality of logic array blocks (LABs) (14). A global interconnect structure (20, 24) is provided for interconnecting a LAB with other LABs. Adjacent or nearby LABs are directly connectable to one another to provide a direct carry chain (70a, 70b) between LABs. The carry chain is enhanced by providing a selector (80) that allows a LAB's carry input to selectively be coupled to either the carry output of an adjacent or nearly LAB or to the global interconnect.

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 interesting 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: 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 method and apparatus for converting a storage device having asynchronous clear and asynchronous preset inputs into an equivalent storage device having asynchronous clear and asynchronous load inputs is provided. If the asynchronous clear/asynchronous preset flip-flop is fed by a preset signal but not a clear signal, the equivalent asynchronous clear/asynchronous load flip-flop is implemented by connecting the preset signal to the clear terminal of the asynchronous clear/asynchronous load flip-flop, disabling the load of the asynchronous clear/asynchronous load flip-flop and inverting the input and output signal of the asynchronous clear/asynchronous preset flip-flop.

Abstract: A programmable logic device (10) has a number of programmable logic elements (LEs) (12) which are grouped together in a plurality of logic array blocks (LABs) (14). A general interconnect structure (20, 30) is provided for interconnecting a LAB with other LABs. A LAB-based interconnect structure (24, 26) is provided for connecting inputs of the LEs in a LAB to a subset of the general interconnect. One or more of output signal lines (55) are included in the LAB-based interconnect structure and are connectable to device output pins. A digital information processing system incorporating the invention is disclosed.

Abstract: A device and method of reducing ground bounce using a CMOS driver 200. The driver includes a first CMOS pass gate 214 and a second CMOS pass gate 222. The first pass gate is used to drive the gate of a PMOS pull-up transistor 210, while the second pass gate is used to drive the gate of an NMOS pull-down transistor 218.

Abstract: A programmable logic device is presented comprising a global interconnect array whose lines are fed via programmable multiplexers to logic array blocks. The global interconnect array lines are fed to the multiplexers in a specific pattern which maximizes the user's ability to route a selected line to the output of a selected multiplexer, while at the same time maintaining higher speed and lower power consumption, and using less chip array than prior art programmable logic devices using programmable interconnect arrays based on erasable programmable read-only memories. A macrocell with product term allocation and adjacent product term stealing is also disclosed. Programmable configuration switches provide product term allocation by directing input product terms to an OR gate or to the secondary inputs to a register. Adjacent product term stealing is accomplished by providing the output of the OR gate of each macrocell as an input to the OR gate of an adjacent macrocell.

Abstract: A programmable logic array integrated circuit device which includes a plurality of regions of programmable logic and interconnection resources for selectively conveying logic signals between various ones of said regions has at least one portion of its interconnection resources enhanced or augmented relative to other similar portions. Any portions of a user's logic that requires more than a usual amount of interconnectivity can be placed in the portion of the device which has the augmented interconnection resources. Examples of augmented interconnection resources are extra conductors for conveying logic signals along one or more rows and/or one or more columns of logic regions on the device.

Abstract: A programmable logic device is presented comprising a global interconnect array whose lines are fed via programmable multiplexers to logic array blocks. The global interconnect array lines are fed to the multiplexers in a specific pattern which maximizes the user's ability to route a selected line to the output of a selected multiplexer, while at the same time maintaining higher speed and lower power consumption, and using less chip array than prior art programmable logic devices using programmable interconnect arrays based on erasable programmable read-only memories.

Abstract: A programmable logic array integrated circuit has a plurality of programmable logic elements grouped into a plurality of mutually exclusive groups. Each group includes signal conductors uniquely associated with that group for conveying signals between the programmable logic elements in that group. Other signal conductors are provided for conveying signals between the groups. Multiplexers can be used in various ways to reduce the number of programmable interconnections required between signal conductors.

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: A programmable logic device is presented comprising a global interconnect array whose lines are fed via programmable multiplexers to logic array blocks. The global interconnect array lines are fed to the multiplexers in a specific pattern which maximizes the user's ability to route a selected line to the output of a selected multiplexer, while at the same time maintaining higher speed and lower power consumption, and using less chip array than prior art programmable logic devices using programmable interconnect arrays based on erasable programmable read-only memories.

Abstract: A programmable logic array integrated circuit has a plurality of programmable logic elements grouped into a plurality of mutually exclusive groups. Each group includes signal conductors uniquely associated with that group for conveying signals between the programmable logic elements in that group. Other signal conductors are provided for conveying signals between the groups. Multiplexers can be used in various ways to reduce the number of programmable interconnections required between signal conductors.

Abstract: Look up tables for use in programmable logic devices are modified to facilitate use of those tables to provide adders (including subtracters) and various types of counters. Each look up table is effectively partitioned into smaller look up tables when an adder or counter is required. One portion of the partitioned table is used to provide a sum out signal, while the other portion of the partitioned table is used to provide a fast carry out signal for application to the next stage of the adder or counter.

Abstract: A programmable logic device is presented comprising a global interconnect array whose lines are fed via programmable multiplexers to logic array blocks. The global interconnect array lines are fed to the multiplexers in a specific pattern which maximizes the user's ability to route a selected line to the output of a selected multiplexer, while at the same time maintaining higher speed and lower power consumption, and using less chip array than prior art programmable logic devices using programmable interconnect arrays based on erasable programmable read-only memories.

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.

Abstract: A programmable logic array integrated circuit has a plurality of programmable logic elements grouped into a plurality of mutually exclusive groups. Each group includes signal conductors uniquely associated with that group for conveying signals between the programmable logic elements in that group. Other signal conductors are provided for conveying signals between the groups. Multiplexers can be used in various ways to reduce the number of programmable interconnections required between signal conductors.

Abstract: A programmable logic device is presented comprising a global interconnect array whose lines are fed via programmable multiplexers to logic array blocks. The global interconnect array lines are fed to the multiplexers in a specific pattern which maximizes the user's ability to route a selected line to the output of a selected multiplexer, while at the same time maintaining higher speed and lower power consumption, and using less chip array than prior art programmable logic devices using programmable interconnect arrays based on erasable programmable read-only memories.