VLSI/PCB placement with obstacles based on sequence-pair

In a typical VLSI/PCB design, some modules are pre-placed in advance, and the other modules are requested to be placed without overlap with these pre-placed modules. The presence of such obstacles introduces inconsistency to a coding scheme, called sequence-pair, which has been proposed for an obstacle free placement problem. We solve this diculty by proposing a procedure, called \adaptation", which transforms inconsistent sequence-pair to consistent one, with utmost consideration for minimizing the modication. It is shown that a simulated annealing is well organized to test only feasible placements with the adaptation procedure. Using the adaptation, an MCNC benchmark data, ami49, is packed with 20% of the modules being pre-placed. Further, a PCB example which includes 32 free modules and 4 pre-placed modules (connectors) is laid out successfully by our method with a conventional wiring estimation followed by a commercial router.

• Type: Conference
• Year: 1997
• Where: ISPD
• Authors: Hiroshi Murata, Kunihiro Fujiyoshi, Mineo Kaneko
• Keywords: Hardware, ISPD 1997, Obstacles Introduces Inconsistency, Pre-placed Modules, Typical Vlsi/pcb Design