Lucent Technologies Inc.

William B Andrews

Satwant Singh

Barry K Britton

Richard G Stuby, Jr

Ho Trong Nguyen

Gary P Powell

James F Hoff

Kai-Kit Ngai

Zeljko Zilic

Carolyn W Spivak

Ronald T Modo

Lorraine L Schadt

Thomas J Hickey

The invention provides an input/output (I/O) signaling voltage range discriminator (and corresponding method) which is used to control a configurable logic device such as a configurable I/O buffer in a second electronic circuit in response to a detected signaling voltage range of a first electronic circuit. The discriminator outputs an indication of the signaling voltage range of the first electronic circuit to a configurable I/O buffer enabling it to adapt to the signaling levels used by the first electronic circuit. The I/O buffer, based on the indication provided by the discriminator, can then configure its logic to become tolerant and/or compatible with digital signals transferred to and from the first electronic circuit.

Signaling voltage range discriminator

The FPGA has an array of programmable logic cells (PLCs) surrounded by a ring of programmable input/output cells (PICs). In one embodiment, the pads of each pair of adjacent PICs, as well as internal routing resources of each of the two PICs, are programmably connected to a single global-signal spine, and the spine is programmably connected directly to only half of the perpendicular branches. Each of the branches can then connect to the cells in two adjacent rows/columns of the array to provide a global signal to any of the cells in the array while only using a branch per every two rows/columns of the device. The reduced number of spine-to-branch connections reduces the capacitive loading on the spines, thereby increasing the speed at which global signals can be transmitted. In addition, sharing spines between adjacent PICs reduces the number of spines in the FPGA by half, thereby providing additional layout space for other resources. Sharing branches also has the same effect as sharing spines in that the number of branches is reduced by half, also increasing global signal speed. These advantages are achieved without reducing the programming flexibility of the FPGA.

Global signal distribution with reduced routing tracks in an FPGA

A field-programmable gate array (FPGA) having at least one programmable cell (e.g., an input/output (I/O) cell) having an output node circuit (e.g., a pad circuit) in which the output data signal and the tri-state signal are applied to a multiplexer that drives the tri-state port of an output buffer in the output node circuit. This configuration enables the output node circuit to be configured for open drain drive mode operations in a fast, predictable manner that does not need to rely on the FPGA's general routing resources.

FPGA having predictable open-drain drive mode

A single integrated circuit (IC) having one or more regions of mask-programmed device (MPD) logic for implementing permanent functions and one or more regions of field-programmable gate-array (FPGA) logic for implementing user-specified functions. The FPGA-type logic provides programming flexibility, while the MPD-type logic provides size, speed, functionality, and dollar cost advantages. In one embodiment, a hybrid IC has an array of programmable logic cells (PLCs) implemented using FPGA-type logic, an application-specific block (ASB) implemented using MPD-type logic, and a ring of pads. Fast interface switch hierarchy (FISH) cells provide the interface between the PLC array and the pads, between the PLC array and the ASB, and between the ASB and the pad ring. Muxes in the FISH cells can be programmed to cause the FISH cells to operate either (1) as programmable interface cells (PICs) that provide a direct interface between the PLC array and the pad ring or (2) as ASB-interface cells (AICs) that (a) provide interfaces between the PLC array and the ASB and (b) control interfaces between the ASB and the pad ring.

Hybrid programmable gate arrays

Growing community of inventors

Long Pond, PA, United States of America

William B Andrews