Technical Insights

Interoperability and RapidIO-based Products

By Jim Parisien, Product Manager, Product Marketing Group
Tundra Semiconductor

Interoperability plays a key role with all protocol standards in establishing faith that multi-vendor devices can interoperate. However, not all interoperability testing is created equal.

The PCI-SIG does much of their interoperability testing through plugfests. Upon meeting some basic entry criteria semiconductor or board vendors gather at a plugfest event to determine if their wares interoperate. In the PC and server world, this consists of bringing a motherboard or adapter card to the event. The software used is typically Windows running on a Pentium processor for a motherboard or a Windows driver for the adapter card. In a simple form factor and software environment such as this, a plugfest can be an effective tool to quickly, albeit qualitatively, gain a sense of interoperability.

This gets far more complicated as we examine embedded applications where form factors vary considerably. For example, CompactPCI (cPCI) comes in 3U and 6U heights and supports many different real time operating systems (RTOSs). Many features such as Hot Swap are optional, yet still need testing. As form factor, RTOS, and sets of capabilities vendors wish to test stray further from an ideal PC environment, the ability to assure customers that a device or card is truly “interoperable” becomes limited if a plugfest is the only tool used. It is precisely this limitation that very often has left OEMs to bear the burden of the due diligence required to verify interoperability. This is one reason why system level prototyping has always been so important to an OEM in de-risking a program. It is also why prototyping and system level integration can be so expensive and time consuming.

The reality is that form factors and RTOS in embedded applications will always be diverse. In fact, as we introduce standards like RapidIO where error recovery is built into hardware, interoperability becomes more complicated. Plugfests are adequate instruments for qualitatively testing components when they work; but they are not effective in testing how devices recover when things inevitably go wrong.

The truth is end-users can’t afford problems (a “Blue Screen” during a 911 call would be disastrous) and OEMs can no longer afford to bear the weight of interoperability testing during product integration. Embedded system protocols like RapidIO require a rigorous interoperability testing approach that provides OEMs with a quantitative analysis of multi-vendor interoperability. While embedded protocols like RapidIO are designed to detect errors and recover in predictable ways that are clearly specified, true interoperability testing for RapidIO requires them to go beyond testing what works; it requires vendors to break the protocol by injecting errors and assessing whether the device under test recovers appropriately.

This class of interoperability testing goes beyond what can be covered during a qualitative plugfest. It pushes the breadth and depth of interoperability testing across different vendor devices and across protocol violations. Plugfests will continue to have a role within RapidIO product development, but one that will primarily be associated with demonstrations of interoperability rather than a means of achieving it.

Recently Tundra announced the RapidIO Interoperability Lab (RIOLAB™) at the TI Developers forum. This facility will be an independent interoperability lab designed to meet the interoperability testing needs of commercial semiconductor vendors, as well as ASIC and FPGA developers. It will provide OEMs with a single source of consistent and independent reports that they need to develop products with confidence. The RIOLAB will remove the burden of proving device interoperability from an OEM’s shoulders and allow them to focus on system design and integration issues. This lab is an excellent sign of a maturing ecosystem. It will ensure interoperability by design and ultimately help OEMs get to market faster.

For information on Tundra Semiconductor, visit http://www.Tundra.com. For information on the RIOLAB, visit: http://www.rapidio.org/news/pr/view?item_key=f316e8cbc17874d764868c7aa7f29a5405875e1f