METHOD AND APPARATUS FOR PROVIDING TIMING INFORMATION WHILE DESIGNING A MULTI-CELL CIRCUIT

摘要

A method and apparatus are described for providing timing information to a view placement interactive (VPI) tool user designing a multi-cell circuit. A circuit design comprising a plurality of cells is displayed to the user. Each cell includes a pre-characterized circuit structure. A graphical user interface (GUI) may be used to request a cell placement change, a design connectivity change or a cell type change. The circuit design is modified to implement the requested change, an incremental static timing analysis is performed, and the resulting timing information associated with the requested change is presented on the displayed circuit design. Timing information may be displayed directly on a cell that receives an output from the particular cell, and/or may be displayed adjacent to the particular cell. The timing information may include current and previous frequency slack information associated with each input and output pin of the particular cell.