The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 02, 2004
Filed:
Nov. 05, 2002
Lattice Semiconductor Corporation, Hillsboro, OR (US);
Abstract
A method for placing configurable logic blocks (CLBs) in a PLD, such as an FPGA. In one embodiment, after packing gates/clusters into blocks and then assigning those blocks to CLBs to generate an initial placement, the packing and/or placement of CLBs is changed prior to performing CLB routing. For each node of the most critical of the K most critical paths in the initial placement, moving the node to a different CLB is considered in order to reduce the criticality of that path. A move is applied if certain acceptability conditions are met. After the most critical path is improved, the criticality of the K paths is updated, and the procedure is repeated for the new most critical of the K updated paths. The method, which can be automated to reduce human intervention in the design process, improves circuit performance, e.g., by enabling higher circuit operation frequencies.