Optimal channel pin assignment

The authors study the channel pin assignment (CPA) problem subject to position constraints, order constraints, and separation constraints. The problem is to assign two sets of terminals to the top and the bottom of a channel to minimize channel density. It is shown that the problem is NP-hard in general and polynomial time-optimal algorithms are presented for a case where the relative orderings of the terminals on the top and the bottom of the channel are completely fixed. The problem of channel routing with movable modules is introduced, and it is shown that it is a special case of the CPA problem under the formulation, and can be solved optimally in polynomial time. How the algorithms can be incorporated into standard-cell and building-block layout systems is discussed. Experimental results indicate that substantial reduction in channel density can be obtained by allowing movable terminals. >

[1]  Sartaj Sahni,et al.  Maximum Alignment of Interchageable Terminals , 1988, IEEE Trans. Computers.

[2]  Thomas G. Szymanski.  Dogleg Channel Routing is NP-Complete , 1985, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems.

[3]  Frank Thomson Leighton,et al.  An approximation algorithm for manhattan routing , 1983, STOC '83.

[4]  Sartaj Sahni,et al.  Two NP-hard interchangeable terminal problems , 1988, IEEE Trans. Comput. Aided Des. Integr. Circuits Syst..

[5]  G. Persky.  PRO - an automatic string placement program for polycell layout , 1976, DAC '76.

[6]  Ronald L. Rivest,et al.  A "Greedy" Channel Router , 1982, DAC 1982.

[7]  R. Rivest,et al.  New Lower Bounds for Channel Width , 1981 .

[8]  C. L. Liu,et al.  Permutation Channel Routing , 1988 .

[9]  Akihiro Hashimoto,et al.  Wire routing by optimizing channel assignment within large apertures , 1971, DAC.

[10]  R. Pelavin,et al.  Hierarchical channel router , 1988, 25 years of DAC.

[11]  David N. Deutsch.  A “DOGLEG” channel router , 1976, DAC 1976.

[12]  Ron Y. Pinter,et al.  On minimizing channel density by lateral shifting , 1983 .

[13]  Mikhail J. Atallah,et al.  Optimal Rotation Problems in Channel Routing , 1986, IEEE Transactions on Computers.

[14]  Takeshi Yoshimura,et al.  Efficient Algorithms for Channel Routing , 1982, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems.

[15]  Chak-Kuen Wong,et al.  Optimal Wiring of Movable Terminals , 1983, IEEE Transactions on Computers.

[16]  Hideaki Kobayashi,et al.  Efficient Algorithms for Routing Interchangeable Terminals , 1985, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems.