摘要:
An electronic design automation tool embodiment uses a single slack graph structure throughout a process to provide communication between a placer (performing placement) and a timing constraint generator (performing slack distribution). The tool includes a slack graph generator, a timing calculator, a timing analyzer, a timing constraint generator and a net bounding box generator. A list of net constraints and a list of complete path constraints are fed to the slack graph generator during operation. Timing calculations from the delay calculator and zero net RC delays from a clustering process in a placer also provide input to the slack graph generator. The list of net constraints, a list of pin-to-pin constraints and a set of specifications for system clocking are input to the timing analyzer. The timing constraint generator receives a composite slack graph from the timing calculator, slack graph generator and timing analyzer. A refined slack graph is output to the net timing constraint generator for mincut placement and placement on an iterative basis. The net timing constraint can be presented in many format, such as limit on net bounding box.
摘要:
An electronic design automation tool embodiment of the present invention comprises a five step process. In a first step, for each pin-master of arbitrary shape in a cell-master a pin access direction is identified, a region in which placing a via will connect a pin to a metal layer, and cause no design rule violation to other pin-masters, is physical bounded on the surface of a chip. Such a region is defined to be a "via-region" of the pin-master. In a second step, at least one "via-spot" within each via-region is identified that violates no design rules if vias are placed at these points. In a third step, vias are placed on each cell instance according to their via-spots. In a fourth step, a "maze-routing" is done to connect the neighboring same net pins by metal-1. In a fifth step, the vias on the pins connected by the maze-router are removed, leaving only one via on a pin if the connection for a current net is not complete.