Obstacle-avoiding router for custom VLSI
Magic's automatic routing system combines the flexibility of hand routing with the speed and quality of automatic channel routers by allowing chip designers to prewire selected nets by hand. The router then works around this previously-placed layout, called obstacles, to automatically wire the remaining nets. This ability to partially hand route an integrated circuit gives designers complete control over critical paths, power and ground routing, and other special nets. At the same time, the router provides a fast way to make the remaining connections in the design. The system's novel features include a fast channel decomposer, an obstacle-avoiding global router, and an obstacle avoiding switchbox router. The router's channel decomposition algorithm relies on a corner stitched data structure to efficiently produce a small number of large channels. The global router considers obstacles during path generation, trading off net length and channel complexity to simplify the subsequent channel routing task. While able to cope with obstacles, Magic's switchbox router is still comparable to the best traditional (non-obstacle-avoiding) channel routers. The router's obstacle-avoidance features rely on two underlying concepts: (1) a preferred direction for crossing an obstacle, and (2) hazards or areas the routing should avoid.
- Research Organization:
- California Univ., Berkeley (USA)
- OSTI ID:
- 7127211
- Country of Publication:
- United States
- Language:
- English
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