Technology deployed
Figure 2 Each CPU board can be plugged into every peripheral slot because each slot is identical.
Enter CompactPCI Serial
Because its roots lie in a technology with broad market applicability, CompactPCI Serial covers a wide range of applications across several embedded markets. Not only did all technical options need to be considered in the standard’s development, but these features also had to remain cost-effective, one of the primary benefits of the original CompactPCI technology. Important to note is that CompactPCI Serial remains backward compatible to CompactPCI PlusIO and CompactPCI, so it can interface with older systems, too. The result is a standard that is as suited for a simple industry PC as it is for a complex control system up to redundant systems and highly complex computer clusters. Existing solutions from the consumer market can be adapted very easily to CompactPCI PlusIO and CompactPCI Serial. For example, an ordinary 2.5” or 3.5” hard disk can be fitted to a CompactPCI Serial plug-in board and linked into the system via SATA without any protocol adaptation. Similarly, a USB flash memory drive or a WiFi stick can be mounted on a board and linked to the processor board via the USB bus present on every slot. The possibilities are enormous and the user can benefit greatly from the existing PC market. And, CompactPCI Serial can be applied in harsh as well as safety-critical environments in addition to these many sub-markets and all areas with electronics in mobile applications, especially on rail and road, in ships and avionics, and research and development.
Expanding the Ecosystem
Emphasis in the development of this new architecture has been placed on retaining the CompactPCI ecosystem that requires considerations for not only hardware but also for additional factors, such as the knowledge and experience of system designers. The standard has been deliberately developed around the familiar 19-inch technology. Mechanically speaking, this allows both “old” parallel boards and new serial boards to operate side by side in the same chassis. Although VITA 46 VPX is also based on the industry-standard 19-inch platform and incorporates high-speed interfaces, the complexity of its implementation may preclude its use in
Figure 3 New SBCs built on CompactPCI Serial provide a host of connection options.
some environments, especially in cost-sensitive industrial applications. The alternative of using the more cost-effective CompactPCI Serial technology is now a reality. Its attributes, such as the high-speed capabilities available through the new connector, set the stage for additional uses of this technology into applications where CompactPCI would traditionally have failed. But the connector does more than just provide CompactPCI with the benefit of faster transmission. It saves significant costs as a component itself as well as provides increased robustness to enhance system reliability, enabling CompactPCI Serial to be used in more harsh applications than this platform previously allowed. Additional cost-savings are seen in system integration, since the architecture does not require a separate switch fabric infrastructure, greatly simplifying the implementation of CompactPCI Serial.
Examining the Inner Workings
Any system built needs to have its parameters defined for the specific application, and a designer using CompactPCI Serial will face a similar set of questions. Considerations need to be made to determine which serial interconnect is the best to use, such as Ethernet for star and mesh architectures, SATA for RAID systems, USB for wireless connection, PCI Express for super-fast graphics and so on. The simple star topology used in CompactPCI Serial eliminates the need for bridges or switches in a system with up to nine slots, because the system slot supports up to eight peripheral slots. In principle all peripheral slots are identical. Only two are connected via extra wide PCI Express links (Fat Pipes), which can be used for high-end graphics extensions, for example (Figure 2). The 19” racks used by CompactPCI Serial are COTS, as are the PSUs and fans. The backplanes are standard components in most RTC MAGAZINE MAY 2011
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