1 Caipirinha: A Free Graphical Viewer for Berkeley Spice Luciano Volcan Agostini and Alex Rocha Prado {agostini, alexrp} @inf.ufrgs.br Federal University of Rio Grande do Sul - Microelectronics Group Caixa Postal 15 064 - Porto Alegre – Brazil Abstract This paper presents Caipirinha viewer, a free software to be used in simulations generated by Spice like simulators. This viewer was designed for Windows and can be used with free Berkeley Spice. The use of a free electrical simulator and a free graphical viewer are a good alternative to be used in designs and simulations at the academic environment. Caipirinha is a simple and recent software then there is a lot of work to improve it, with the design of a more friendly interface and with the insertion of new functions, but this first version is enough to be used with the necessary accuracy for a lot of applications. 1. Introduction The idea of the design of a free viewer to be used in spice simulations arises when a group of UFRGS master students was working in an echo canceller chip design [PRA 00], [AGO 00], [AGO 01] and noted that the available version of Hspice simulator (for Solaris) are not capable to run a correct simulation of the CMOS model BSIM3v3. Such the echo canceller design uses hundreds of transistors, the available shareware simulators and viewers, like Pspice, did not permit this simulations. Then the use of a free Berkeley Spice [UCB 01] becomes the natural choice. A free source code of Berkeley Spice for Linux was downloaded and this version was modified to be compiled for Windows. The problem then was the graphical viewer, that was not found in the internet software repositories. The alternative was the design of a new and free viewer. The name choose to this new viewer was Caipirinha. Caipirinha was designed in Delphi [CAN 96] because this language has a very high level of programmability and has a lot of predefined components like menus, bottoms, windows, etc, making easy the Caipirinha design. The waveforms area was designed starting from a standard graphic component preinstalled in Delphi packages. The platform choose was Windows because it had, to the authors, the best time-to- finish relationship in the graphic interface and in the software core design. Besides Windows is a very popular operational system and the simulations could be ran at the University or at home, with an important flexibility and independence of computer or place. Caipirinha viewer was very useful to the echo canceller design, specially in the RAM design. Caipirinha together with Berkeley Spice was used in simulations with more than 1,500 transistors and with more than 25 waveforms simultaneously. Caipirinha is a good tool for didactical goals, since it is a free and simple tool and it can be used together with a free and reliable Spice version. Caipirinha viewer and Berkeley Spice are downloadable in [GME 01] and [LUC 01].