A Performance-Driven Circuit Bipartitioning Method Considering Time-Multiplexed I/Os

Masato INAGI  Yasuhiro TAKASHIMA  Yuichi NAKAMURA  Yoji KAJITANI 

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences  Vol.E90-A  No.5  pp.924-931
Publication Date: 2007/05/01
Online ISSN: 1745-1337
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
circuit partitioning,  time-multiplexed I/O,  FPGA,  pin constraint, 

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Summary: 
Lately, time-multiplexed I/Os for multi-device implementations (e.g., multi-FPGA systems), have come into practical use. They realize multiple I/O signal transmissions between two devices in one system clock cycle using one I/O wire between the devices and multiple I/O clock cycles. Though they ease the limitation of the number of I/O-pins of each device, the system clock period becomes much longer approximately in proprotion to the maximum number of multiplexed I/Os on a signal path. There is no conventional partitioning algorithm considering the effect of time-multiplexed I/Os directly. We introduce a new cost function for evaluating the suitability of a bipartition for multi-device implementations with time-multiplexed I/Os. We propose a performance-driven bipartitioning method VIOP which minimizes the value of the cost function. Our method VIOP combines three algorithms, such that i) min-cut partitioning, ii) coarse performance-driven partitioning, iii) fine performance-driven partitioning. For min-cut partitioning and coarse performance-driven partitioning, we employ a well-known conventional bipartitioning algorithms CLIP-FM and DUBA, respectively. For fine performance-driven partitioning for the final improvement of a partition, we propose a partitioning algorithm CAVP. By our method VIOP, the average cost was improved by 10.4% compared with the well-known algorithms.