Programmable routing structures providing shorter timing delays for input/output signals
First Claim
1. A programmable logic integrated circuit comprising:
- a plurality of I/O pads that allow external access to the integrated circuit;
a plurality of programmable global routing conductors;
a plurality of circuit elements;
programmable dedicated routing conductors coupled to transmit signals between the I/O pads and the circuit elements, bypassing the global routing conductors; and
at least one multiplexer coupling a set of the plurality of I/O pads directly to the programmable dedicated routing conductors.
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Accused Products
Abstract
Techniques are provided for routing signals to and from input/output pads on a programmable chip that reduce signal delay times. A programmable routing structure is provided that is dedicated to routing signals to and from the input/output (I/O) pads. The programmable routing structure can include long conductors that transmit signals across the chip quickly without the delay encountered in shorter routing conductors. Signals can be routed to and from the I/O pads through vertical and horizontal dedicated routing conductors that bypass global routing conductors. The dedicated I/O routing structure allows signals to be driven onto the chip and off chip more quickly can be achieved through standard programmable routing structures. The dedicated I/O routing structure can be depopulated to reduce the number of programmable connections between the individual conductors, decreasing die area requirements.
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Citations
19 Claims
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1. A programmable logic integrated circuit comprising:
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a plurality of I/O pads that allow external access to the integrated circuit; a plurality of programmable global routing conductors; a plurality of circuit elements; programmable dedicated routing conductors coupled to transmit signals between the I/O pads and the circuit elements, bypassing the global routing conductors; and at least one multiplexer coupling a set of the plurality of I/O pads directly to the programmable dedicated routing conductors. - View Dependent Claims (2, 3, 4, 5, 7, 8, 9)
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6. A programmable logic integrated circuit comprising:
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a plurality of I/O pads that allow external access to the integrated circuit; a plurality of programmable global routine conductors; a plurality of circuit elements; programmable dedicated routing conductors coupled to transmit signals between the I/O pads and the circuit elements, bypassing the global routing conductors, a first set of the dedicated routing conductors being programmably coupled to the I/O pads and a second set of the dedicated routing conductors being perpendicular to and programmably coupled to the first set of dedicated routing conductors; and a set of multiplexers that couples the first set of dedicated routing conductors to the second set of dedicated routing conductors, wherein some of the set of multiplexers couple I/O pads directly to the second set of dedicated routing conductors.
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10. A programmable logic integrated circuit comprising:
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rows of programmable logic elements that are configurable to perform combinatorial and sequential functions; programmable global routing conductors aligned in a first direction and a second direction perpendicular to the first direction; a plurality of I/O pads of the integrated circuit; dedicated routing conductors coupled to transmit signals between the I/O pads and the logic elements without routing through the global routing conductors; and at least one multiplexer coupling a set of the plurality of I/O pads directly to the dedicated routing conductors, wherein the dedicated routing conductors are aligned in the first and the second directions, and the dedicated routing conductors routed in the first direction are programmably connectable to the dedicated routing conductors routed in the second direction by depopulated programmable logic connections. - View Dependent Claims (11, 12)
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13. A method for forming a programmable logic integrated circuit, the method comprising:
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providing pads that allow external access to the programmable logic integrated circuit; providing a plurality of global vertical and horizontal programmable routing conductors; providing a plurality of circuit elements; providing programmable dedicated routing conductors that are coupled to transmit signals between the pads and the circuit elements without routing the signals through the global programmable routing conductors; and providing multiplexers that couple the pads directly to the dedicated routing conductors. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification