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MIPI Interoperability and Conformance: Interview with David Woolf (Part 3)

We are back with part#3 and FINAL of the interview with Mr. David Woolf, Senior Engineer at UNH-IOL, which actively engages in interoperability and conformance tests for various MIPI protocols. If you missed the first part of the interview you can find it here and second part here.

Question: David, what do you think vendors such as Synopsys can do to strengthen the MIPI eco-system?

Answer: Synopsys is in a unique position, having customers in many corners of MIPI, they can have a big influence. I’m happy to see Synopsys engaging early on conformance and interop testing. I think that will lead to smoother integration for its customers later on, which will strengthen the whole MIPI community.

Question: What is your perspective about MIPI protocols enabled by M-PHY and D-PHY and how do you think these could be tested to avoid failures in the field?

Answer: Looking ahead, I hope to see future interfaces like M-PHY and the protocols that ride on top of them like LLI and UniPro, and eventually CSI-3 and DSI-2, tested in the same way we’ve we’re testing D-PHY, CSI-2, and DSI. I know UniPro is off to a good start with a series of interop events. The interop events are a great opportunity not only to prove that an interface works, but to meet your counterparts at other companies. Knowing individuals at other companies and working side by side with them at an interop event contributes to unity within the industry. Of course many of these companies are competitors. But interoperable products lead to a more fruitful marketplace, which is good for all of us.

Question: What are the plans for interoperability in 2012?

We’re hoping to have several MIPI Interop Workshops in 2012. We just had the first ever MIPI BIF Interop Workshop in January, and I anticipate there will be another one this year. We had a MIPI Display Interop Workshop in March, which several application processor and display peripheral companies have already signed up for. There’s a chance we’ll have an LLI Interop Workshop this year too, which could be the first interop workshop with M-PHY silicon.

Question: Can you share with us summary of the results from an upcoming recent interop and conformance event which can illustrate the benefits we discussed here

Answer: There are several benefits to the interop events. One that’s often overlooked is the potential for these events to help improve the specification. Of course each individual company benefits by being able to prove their designs, and make contacts at other companies, and get a third party report showing their interoperabilty. But there is a benefit to the whole MIPI community as well. It’s when doing these interop tests that we may find cases where different companies have interpreted the specification differently. That happened at a recent event where we found an ambiguity in how DSI peripherals may respond to a Bus Turn Around request. We found that in some cases, if a host made a query to a DSI peripheral followed by a Bus Turn Around request, we would get a different response to the query from the peripheral depending on how quickly the Bus Turn Around request was sent after the query. Essentially, if the Bus Turn Around request was sent too quickly, you could get the wrong data back in the response from the DSI peripheral. This was an interoperability problem, but it proved to be an opportunity to improve the DSI specification. UNH-IOL worked with the MIPI Display Working Group to clarify that portion of the DSI specification. That benefitted the entire MIPI community.

Hezi Saar: David, thank you for sharing your perspective on this topic. I believe this interview will be used by many to educate themselves about what they need to take care of when they develop their next MIPI interface.

David: Thank you for the opportunity.

That’s all for now, I hope you enjoyed reading please visit next time and forward if you found this interesting.

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