Look-up table based logic element with complete permutability of the inputs to the secondary signals
AssigneesAltera Corporation, Quickturn Design Systems, Inc.
InventorsKevin A. Norman, Rakesh H. Patel, Stephen P. Sample, Michael R. Butts
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Abstract
A logic element for a programmable logic device. The logic element includes a look-up table (400) for implementing logical functions, a programmable delay block (415), a storage block (430) configurable as a latch or a flip-flop, and a diagnostic shadow latch (435). A plurality of inputs (410) to the logic element and complements of these inputs are available to control the secondary functions of the storage block (430).
Claims27
In a programmable logic device, a logic element comprising:
- a memory;
- a multiplexor having a plurality of control inputs and a plurality of data inputs, the plurality of data inputs being coupled to said memory;
- a storage block coupled to said multiplexor, wherein said storage block stores an output of said multiplexor;
- a first plurality of inputs coupled to said control inputs of said multiplexor, said first plurality of inputs being sufficient in number to uniquely select between each of the plurality of data inputs to said multiplexor, each of said first plurality of inputs being programmably coupled to said storage block;
- a combinatorial output, coupled to said multiplexor;
- and
- a registered output, coupled to said storage block.
A logic element for an integrated circuit, comprising:
- a memory having a plurality of outputs;
- a multiplexor having a plurality of control inputs and a plurality of data inputs, the plurality of data inputs being coupled to said memory;
- a storage block coupled to said multiplexor, wherein said storage block stores an output of said multiplexor;
- a first plurality of inputs coupled to said control inputs of said multiplexor, said first plurality of inputs being sufficient in number to uniquely select between each of the plurality of data inputs to said multiplexor, each of said first plurality of inputs being programmably coupled to said storage block;
- a second plurality of inputs coupled to said storage block providing complementary signals of each of said first plurality of inputs, respectively;
- a combinatorial output, coupled to said multiplexor;
- and
- a registered output, coupled to said storage block.
In a programmable logic device, a logic element comprising:
- a memory for storing a plurality of data entries;
- a storage element coupled to the memory;
- a plurality of control inputs for selecting at least one of said data entries, said plurality of control inputs being programmably coupled to said storage element;
- a first output port for outputting said selected data entry;
- and
- a second output port coupled to said storage element for outputting said stored data entry.
Dependencies are inferred from the claim text.