One of the earliest science experiments I can remember doing was crushing red cabbage in a mortar and pestle with some sort of alcohol. The resulting purple liquid would turn red in acid and blue in alkali. True litmus is not extracted from red cabbage but from various lichens. I think they are more sensitive than cabbage. Red (really pink) litmus paper turns blue in alkali, and blue litmus turns red in acid. Now that's bringing back smells of school chemistry labs. No wonder Proust stuck to madeleines. It seems litmus was first used in 1300AD for checking clock-domain-crossing...no wait, that's Conformal Litmus. Conformal Litmus Cadence announced Conformal Litmus at CDNLive Japan. Conformal Litmus is a next-generation tool that provides constraint signoff and clock-domain-crossing (CDC) signoff. Like other Cadence tools ending in "-us", it shares the same timing engine. So Litmus uses the same engine as Tempus, Genus, Innovus, and others. This provides 100% signoff timing accuracy at the RTL level. It also makes use of multi-CPU parallelization. Verification can be parallelized across multiple cores, delivering up to 10X faster turnaround time on SoC designs (compared to the previous tool). Designs used to have a single clock, but now designs with hundreds of clock domains are common. Everywhere signals have to cross from one clock domain to another, something special needs to be done at the boundary, such as adding FIFOs or synchronizers. In a big chip, which may have millions of CDC paths, the only approach is a full guarantee of correctness. This is where Conformal Litmus comes in to create that guarantee, or flag the places where there are CDC errors. CDC signoff verifies structural correctness of CDC in the design from early RTL through implementation flows. Smart analysis and reporting features provide rapid signoff capabilities, potentially saving weeks to months in the design schedule. One problem with modern SoC designs is that IP blocks come with their own constraints, but the group assembling the SoC didn't create them and doesn't want to have to do a deep dive into understanding them fully. On the other hand, the SoC has to work, so the constraints all need to be checked. Conformal Litmus can handle these hierarchical designs correctly. To sign off the constraints requires correctness and completeness of constraints at the block level and lets users perform hierarchical block versus top consistency checks at the SoC integration level. The Conformal Litmus smart analysis generates accurate, low-false-positive reports that shorten debug time and helps users achieve signoff-quality constraints rapidly. One of the early customers was Renasas. Hideyuki Okabe, the director of the digital design technology department loves the speedup: With the multi-CPU parallelization capabilities, we are able to complete runs on designs as large as 50M instances in under 10 hours. Vikram Kurlaia of Invecas likes the ease of use for CDC: The IP and ASICs we develop have extremely complex CDC structures, including handshake synchronizers, bus synchronizers, and FIFOs. CDC signoff tends to be cumbersome since often the engineer entrusted with CDC verification has no knowledge of the design intent. Cadence Conformal Litmus presents the results in a very intuitive way. More Information For more information, see the Conformal Litmus product page . Sign up for Sunday Brunch, the weekly Breakfast Bytes email.![]()
↧
