A method for optimal track assignment in a grid-based channel router Initially, interconnection information is extracted from a global routing result Multiple pin nets derived from the interconnection information are decomposed into simpler mapped segments A channel grid map is then built and marked with existing objects Next, a vertical constraint graph specifying the relative positions of the mapped segments is constructed A first track is computed A track assignment loop is repeated until all requisite connections are realized The track assignment loop includes the steps of breaking cycles and long paths and collecting a set of feasible links One or more weighting functions are assigned to each such feasible link A dynamic programming approach is used to select an optimal set of feasible links according to the weighting functions In addition, an optimal set of feasible links corresponding to unpreferred layers is collected by applying dynamic programming Finally, the chosen feasible links are physically realized on the current track

Method for optimizing track assignment in a grid-based channel router

A new design for testability technique, the bit-splitting for testability enhancement in scan-based design, is presented. The idea is to split some inputs into two independent variables to make the original circuit more controllable and thus more testable. Theoretical study and experiments with two-level circuits indicate that this method can easily provide 100% Single-Path-Sensitization Path Delay Fault Testability (SPDFT). Fault coverage can also be improved for the multi-level circuits and when constrained transformations are used, multi-level circuit can also be made 100% SPDFT. >

http://ieeexplore.ieee.org/iel2/3140/8949/00393389.pdf

Bit-splitting for testability enhancement in scan-based design

In the past decade, D. Deutsch's (1976) difficult example has been used extensively as a benchmark to test various channel-routing algorithms. Since more and more channel routers are able to achieve an optimal or near-optimal solution for the original difficult example. Deutsch recently (1989) proposed two new and more difficult channel-routing problems to provide new challenges for researchers in this area. Due to off-grid terminal locations in the new examples, the number of vertical constraints are almost doubled, and many cycles are present in the vertical constraint graph. A gridless channel router which intelligently generates doglegs to break cycles and vertical constraints and successfully completes the routing of Deutsch's new and more difficult examples is presented. This gridless router is among the first routers to report results on these new benchmarks. >

https://ieeexplore.ieee.org/iel2/853/3167/00101910.pdf

H.H. Chen

Papers

Breaking cycles and vertical constraints in Deutsch's new and more difficult channel-routing problems