Author: Eelco van der Wal, Chairman PICMG Europe
CompactPCI has been very successful in its 15 years of existence with its support for 6U and 3U systems. However, the move from a parallel bus to a strictly serial solution has not been made yet.
The 2.16 specification, with a CompactPCI packet switching backplane, was a good starting point for integrating parallel and serial busses coherently, combined with 2.17 (StarFabric), 2.18 (Serial RapidIO), 2.20 (Serial Mesh Backplane) or EXP.0 (PCI Express). Within the PICMG organization, the serial busses were originally implemented in the telecom-centric AdvancedTCA concept and its more compact microTCA derivative. Both systems are built around switched fabrics which can incur additional costs for systems that do not need this functionality.
Now a new technology adds serial busses to the CompactPCI standard to extend its life to the next 15 years. Its name is CompactPCI Plus, and it contains both the CompactPCI PlusIO (2.30) specification for the extension by serial I/O and CompactPCI Serial (CPCI-S.0). These two form the future serial approach, making all modern serial interfaces cost-effectively available directly on the system level.
CompactPCI PlusIO expands the system slot by serial signals on the J2 connector. This I/O definition is fully backward compatible to 32-bit CompactPCI and will interoperate with existing 32-bit systems. It also allows the implementation of hybrid systems: CompactPCI with a CompactPCI PlusIO system slot and up to four CompactPCI Serial peripheral slots in a star topology.
CompactPCI Serial defines new system and peripheral slots in combination with connectors for at least 10 Gb performance, and specifies the support of PCI Express, Ethernet, SATA/SAS and USB concurrently. The system slot supports up to eight peripheral slots.
Writing specifications is only the first step. Implementing is the next step. And for this a wide community is needed, ranging from connector suppliers, backplane suppliers, racks, power supplies, and yes – computer modules like processing and I/O. Together with its members PICMG creates ecosystems to support the acceptance of the specifications as well as the multiple sources of supply. For CompactPCI PlusIO nearly 40 companies supported the work. This is a sufficiently high number to create a viable ecosystem contributing to the success of the specification.
With the technical improvements, the smooth transition path, and the broad support from the industry, CompactPCI Plus will certainly have its future, and perhaps change your future.