Xilinx, Inc.

Madabhushi V R Chari

Sudip K Nag

Jason H Anderson

Rajeev Jayaraman

James L Saunders

Kamal Chaudhary

Sandor S Kalman

Matthieu P H Cossoul

Apparatus and methods of testing for bridge faults in nets of the interconnect of a programmable integrated circuit. Each net is sourced by a function generator (e.g., a look up table) configured as a clocked shift register. For each net group, shift registers connecting nets in the group are initialized identically to one value and are initialized to a different unique value from shift registers connecting nets of other net groups. Each shift register stores one bit with a value one and zeros in all other bits. When the shift register is clocked, it provides a single one on one clock cycle and provides zeros in all other clock cycles. At the end of n clock cycles, where n is the length of the shift register, if the load on any net has a value that is different from the value provided by the net's corresponding shift register, a short is detected.

Testing for bridge faults in the interconnect of programmable integrated circuits

Testing of routing resources in a path between network nodes is provided using simpler nodes to replace more complex IP modules which could be programmed into an FPGA after the routing resources are tested. Further, when it is impractical to generate a pattern from a source node S for testing a network path N to a load, subnetworks are created to perform testing. To provide the subnetworks, a source S' is first provided close to node S that generates signal patterns to route through a path N&#x2032; to load L. When it is impractical to test a network path N from source to load L, a load L&#x2032; is further provided close to load L that receives the signal patterns from a routing path N&#x2033; provided from source S. The paths N&#x2032; and N&#x2033; overlap to cover all the routing resources of the path N.

Method to test routed networks

A method and apparatus for placement into a programmable gate array of I/O design objects having different I/O attributes. The I/O attributes of an I/O design object define the electrical characteristics of the design object. The programmable gate array has a plurality of sites (IOBs) arranged into banks supporting a variety of electrical interface characteristics. In an example embodiment, I/O design objects are placed into IOBs of the programmable gate array by first performing simulated annealing that considers conflicts between I/O attributes of I/O design objects as placed into the IOBs. Then, a bipartite matching is performed using placement results from simulated annealing. Finally, if the bipartite matching does not produce a feasible placement, sets of I/O attributes are assigned to the banks based on the previous placement results, and the bipartite matching process is repeated.

Method and apparatus for placement of input-output design objects into a programmable gate array

A method and apparatus for automatic, timing-driven implementation of a circuit design. In one embodiment, the different phases of implementing a circuit design are iteratively performed using timing constraints that are automatically and dynamically generated in each iteration. The process aids in identifying and achieving a maximum performance level of the implemented design. In another embodiment, selected numbers of critical connections are used to dynamically vary the timing constraint. In general, a number of connections is automatically selected from the circuit design and used to derive a new timing constraint to be applied in the next iteration. Slack values associated with paths in the design are also used in deriving the new timing constraint.

Method and apparatus for automatic timing-driven implementation of a circuit design

A method and apparatus for placement into a programmable gate array of input-output (I/O) design objects having different voltage standards. The programmable gate array has a plurality of sites arranged into banks supporting interfaces with a plurality of different input and output voltage standards. In an example embodiment, I/O design objects are placed into IOBs of the programmable gate array by first performing simulated annealing that considers conflicts between design object voltage standards as placed into the IOBs. Then, a bipartite matching is performed using placement results from simulated annealing. Finally, if the bipartite matching does not produce a feasible placement, standards are assigned to the banks based on the previous placement results, and the bipartite matching process is repeated.

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San Jose, CA, United States of America

Madabhushi V R Chari