Abstract: A programmable logic device architecture with a highly routable programmable interconnect structure. The arrangement of the logic array blocks (LABs), programmable interconnect structure, and other logical elements forms a Clos network. After specific constraints have been met, the architecture is guaranteed to route. The architecture is provably routable when there is no fan-out in the middle stage. A LAB (200) comprises an input multiplexer region (504), logic elements (300), input-output pins (516), and output multiplexer region (508).

Abstract: A programmable logic device integrated circuit incorporating a memory block. The memory block (250) is a general-purpose memory configurable as a random access memory (RAM) or a first-in first-out (FIFO) memory. In one embodiment, the organization of memory block (250) may have variable word size and depth size. Memory block (250) is coupled to a programmable interconnect array (213). Signals from the programmable interconnect array (213) may be programmably coupled to the data, address, and control inputs of the memory block. Data output and status flag signals from the memory block are programmably coupled to the programmable interconnect array (213).

Abstract: A programmable logic device architecture with a highly routable programmable interconnect structure. The arrangement of the logic array blocks (LABs), programmable interconnect structure, and other logical elements forms a Clos network. After specific constraints have been met, the architecture is guaranteed to route. The architecture is provably routable when there is no fan-out in the middle stage. A LAB (A-200) comprises an input multiplexer region (A-504), logic elements (A-300), input-output pins (A-516), and output multiplexer region (A-508). Furthermore, a logic device and a method of operating a logic device. The device includes logic elements (B-240) that perform desired logic functions and routing functions. The logic elements (B-240) are arranged in larger logic blocks known as logic array blocks (B-230) that have local interconnection systems. The logic array blocks (B-230) are configured to provide global interconnections.

Abstract: A programmable logic device integrated circuit incorporating a first-in, first-out memory block (250). First-in, first-out memory block (250) is coupled to a programmable interconnect array (213). Signals from the logic array blocks (LABs) (201) are connected to the control inputs of the first-in, first-out memory (250). In one embodiment, the programmable interconnect array (213) may be programmably coupled to the control inputs (259) of the first-in, first-out memory block. Status flag signals (276) from the first-in, first-out memory block (250) are programmably coupled to the programmable interconnect array (213). Data input (263) and data output (261) to first-in, first-out memory block (250) may be coupled to external, off-chip circuitry.

Abstract: A programmable logic device architecture with a highly routable programmable interconnect structure. The arrangement of the logic array blocks (LABs), programmable interconnect structure, and other logical elements forms a Clos network. After specific constraints have been met, the architecture is guaranteed to route. The architecture is provably routable when there is no fan-out in the middle stage. A LAB (200) comprises an input multiplexer region (504), logic elements (300), input-output pins (516), and output multiplexer region (508).

Abstract: A programmable logic device integrated circuit incorporating a first-in, first-out memory block (250). First-in, first-out memory block (250) is coupled to a programmable interconnect array (213). Signals from the logic array blocks (LABs) (201) are connected to the control inputs of the first-in, first-out memory (250). In one embodiment, the programmable interconnect array (213) may be programmably coupled to the control inputs (259) of the first-in, first-out memory block. Status flag signals (276) from the first-in, first-out memory block (250) are programmably coupled to the programmable interconnect array (213). Data input (263) and data output (261) to first-in, first-out memory block (250) may be coupled to external, off-chip circuitry.

Abstract: A programmable logic device integrated circuit incorporating a memory block. The memory block (250) is a general-purpose memory configurable as a random access memory (RAM) or a first-in first-out (FIFO) memory. In one embodiment, the organization of memory block (250) may have variable word size and depth size. Memory block (250) is coupled to a programmable interconnect array (213). Signals from the programmable interconnect array (213) may be programmably coupled to the data, address, and control inputs of the memory block. Data output and status flag signals from the memory block are programmably coupled to the programmable interconnect array (213).

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: 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: A programmable logic device integrated circuit incorporating a first-in, first-out memory block (250). First-in, first-out memory block (250) is coupled to a programmable interconnect array (213). Signals from the logic array blocks (LABs) (201) are connected to the control inputs of the first-in, first-out memory (250). In one embodiment, the programmable interconnect array (213) may be programmably coupled to the control inputs (259) of the first-in, first-out memory block. Status flag signals (276) from the first-in, first-out memory block (250) are programmably coupled to the programmable interconnect array (213). Data input (263) and data output (261) to first-in, first-out memory block (250) may be coupled to external, off-chip circuitry.

Abstract: A programmable logic device integrated circuit incorporating a memory block. The memory block (250) is a general-purpose memory configurable as a random access memory (RAM) or a first-in first-out (FIFO) memory. In one embodiment, the organization of memory block (250) may have variable word size and depth size. Memory block (250) is coupled to a programmable interconnect array (213). Signals from the programmable interconnect array (213) may be programmably coupled to the data, address, and control inputs of the memory block. Data output and status flag signals from the memory block are programmably coupled to the programmable interconnect array (213).

Abstract: A programmable logic device integrated circuit incorporating a first-in, first-out memory block (250). First-in, first-out memory block (250) is coupled to a programmable interconnect array (213). Signals from the logic array blocks (LABs) (201) are connected to the control inputs of the first-in, first-out memory (250). In one embodiment, the programmable interconnect array (213) may be programmably coupled to the control inputs (259) of the first-in, first-out memory block. Status flag signals (276) from the first-in, first-out memory block (250) are programmably coupled to the programmable interconnect array (213). Data input (263) and data output (261) to first-in, first-out memory block (250) may be coupled to external, off-chip circuitry.

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 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: Scan testing of asynchronous logic circuitry is facilitated by gating off the asynchronous inputs to flip-flops during scan testing. If desired, the asynchronous inputs which are gated off in this manner may themselves be tested by connecting them to one or more output terminals or scan registers during testing. Alternatively, the asynchronous inputs which are gated could be tested by selectively enabling the signals at strategic points during scan testing. The number of input terminals required to control the test mode may be reduced by providing registers for storing test control signals applied to normal input terminals at the beginning of a test cycle. Once these test control signals are stored, the normal input terminals are free to return to their normal use.

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: Scan testing of asynchronous logic circuitry is facilitated by gating off the asynchronous inputs to flip-flops during scan testing. If desired, the asynchronous inputs which are gated off in this manner may themselves terminals or scan registers during testing. Alternatively, the asynchronous inputs which are gated could be tested by selectively enabling the signals at strategic points during scan testing. The number of input terminals required to control the test mode may be reduced by providing registers for storing test control signals applied to normal input terminals at the beginning of a test cycle. Once these test control signals are stored, the normal input terminals are free to return to their normal use.