“Agile” Chip Building (CRAFT, ChipKit, Chip Gallery)

Agile and Rapid Design of Research Test Chips

Research test chips are the ultimate experiment to demonstrate the true value of novel computer architecture innovations. They are always very highly regarded by reviewers as the most honest evaluation of a new hardware proposal. In addition, there is a huge pedagogical value in taping out test chips, as it offers insight on the impact of real hardware and microarchitecture details that are critical in guiding higher level architecture decisions and trade-offs. Nonetheless, despite all this, taping out test chips remains a challenge for those who are following this path for the first time. Traditionally, research chips have been time-consuming to design, fabricate and test, and often error prone - potentially requiring re-spins to fix problems.

To help lower the entry barrier for chip tape-outs, we have pioneered an open-source framework, CHIPKIT, centered on agile and reusable themes. Emphasizing reuse greatly reduces development cost and at the same time minimizes the opportunity for silicon bugs, freeing the designer to focus on differentiating features. While agile design seeks to follow a methodology where changes can be readily implemented late into the design cycle, without significant disruption or risk. A full-chip validation methodology, covering the entire design flow, is then adapted onto this system-on-chip scaffold in order to ensure functional correctness. Following the CHIPKIT framework has allowed steady and new tape-outs (a subset illustrated in the gallery below) to be developed with very low-risk, high success rate, and with design and verification efforts reduced by orders of magnitude.