Via Programmable Structured ASIC Architecture “VPEX3” and CAD Design System

Ryohei HORI  Taisuke UEOKA  Taku OTANI  Masaya YOSHIKAWA  Takeshi FUJINO  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E95-A   No.12   pp.2182-2190
Publication Date: 2012/12/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E95.A.2182
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
Category: Physical Level Design
via programmable logic device,  structured ASIC,  exclusive-OR,  middle-volume production,  

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A low-cost and low-power via-programmable structured ASIC architecture named “VPEX3” and a VPEX3-specific CAD system are developed. In the VPEX3 architecture, which is an improved version of the old VPEX and VPEX2 architectures, an arbitrary logic function including sequential logic can be programmed by three via layers. The logic elements (LEs) of VPEX3 are 60% smaller than those of the previous VPEX2, which can be programmed by two via layers. In this paper, we describe a global architecture named Logic Array Block (LAB) composed of LE matrices. The clock lines are buffered in the buffering region on the left and right sides of LAB. Next, a VPEX3-specific CAD system utilizing an academic placement tool named “CAPO” and the “FGR” global router is developed. Since these tools are originally designed for ASICs, we developed CAD tools for supporting a structured ASIC architecture. In particular, we developed a detailed router that assigns via positions on the via-programmable routing fabric. Our CAD system successfully converts the HDL design to GDS-II data format including via-1, 2, 3 layouts, and the successful verification of LVS and DRC on GDSII is achieved. The performance of the VPEX3 architecture and the CAD system is evaluated using ISCAS benchmark circuits. The developed CAD system is used to successfully design a test chip composed of 130110 LEs.