Xilinx, Inc.

Iowa State University Research Foundation Inc

Bodhisattva Das

William C Black

Marwan M Hassoun

Scott Alan Irwin

Matthew Shafer

Edward K F Lee

Method and apparatus for configuring a programmable logic device to perform testing on a signal channel is described. Configurable logic of the programmable logic device is configured for a test mode. Configurable interconnects are configured for communication from or to the configurable logic to or from transceivers coupled to the configurable input/output interconnect to communicate test signals.

Communication signal testing with a programmable logic device

In this invention, three schemes of nonvolatile FPLD structures are proposed using a latch that has been disclosed herein. In the first proposed scheme the latches, which can be designed using either GMR or SDT devices, will work as interconnects in a conventional Programmable Logic Array (PLA). In the second proposed scheme, the latches will constitute the look-up table for a standard PLA. In the third proposed scheme, the latch itself will work as a nonvolatile Programmable Logic Device (PLD) structure. This FPLD latch will have 2 GMR or SDT resistors, instead of just 2, for an n-input logic gate. By programming the resistors differently, in each scheme, numerous different logic functions from the same logic gate can be achieved.

Nonvolatile programmable logic devices

A device and method for sensing the status of a non-volatile magnetic latch. A cross-coupled inverter pair latch cell is employed for the data sensing. During the 'Sense' cycles, the inputs to the latch cell are from spin dependent tunneling effect devices, each located in its respective inverter pair. The SDT magneto-resistive storage devices have complimentary resistance states written into them. A switch, connected to the inverter pairs, is used to reset and initiate a regenerative sequence. Whenever the switch is turned on (reset) and off (regenerate), the latch cell will sense a potential imbalance generated by the magneto-resistive storage devices with complimentary resistance. During regeneration, the imbalance will be amplified and eventually the inverter pairs will reach a logic high or logic low state. The latch can be used as a memory circuit, however, upon loss of power the memory is retained. The state of the circuit is retained inside of SDT components. On-chip current lines are used to control the states of the components.

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Ames, IA, United States of America

Bodhisattva Das