Project AX: an automatic schematic design system. I. Interactive transistor placement

Based on mode structure analysis, circuit patterns, and human factors, the authors are building a high speed placement system which follows the practical circuit design procedures for CMOS digital/analog circuits at the transistor level. Built on top of the X window, the system provides a highly automatic, interactive graphics editor with modularity and easily added-on features. The node-based structure enables the system to work on any kind of CMOS circuits and avoids the patterns deadlock problem. In addition, the authors´ system also has the advantage of speed. Even with up to 50 transistors, there is no waiting time on the placement display once the netlist is in and the program is executed. The authors also consider the importance of the interface problem at the system level for achieving perfect placement and routing. Transistor placement is part of the automatic schematic design system and runs under a network-transparent, multiprocessing, and multiprogramming environment. The design system allows many users to work on the same chip at different levels on different machines.<>