CompactPCI® Serial – Why is it a PICMG Standard?

Version 1

    Author: Manfred Schmitz, CTO MEN Mikro Elektronik


    CompactPCI Serial CPCI-S.0 is a specification for robust, modular computers and a design improvement for the tried and tested CompactPCI PICMG 2.0 specification.


    But is a standard like this still necessary today? Isn't technical development too dynamic, so that a standard is left behind by technology before it is even approved? Do customers still ask for standards after all? Aren't standards talked to death in work groups, and don't the technical solutions remain rather average?


    These are the questions that come up when a work group is founded that has the task of setting up a new specification. Choosing PICMG as an organization has the benefit of unique clarification of all questions regarding IP rights. The rules and regulations of PICMG make sure that nothing is standardized that is protected by patents. This prevents that companies assert a right to claim license fees as soon as products based on the new standard hit the market. This is important for customers.


    The "CompactPCI Serial" work group unites more than 30 companies. It was exciting to see if all of these companies would really pursue a common goal. The technical discussion of all details of the new specification took about a year. It is remarkable that more than a third of all members took part in the standardization work on a regular basis. The companies participating came from all areas and many countries the world over – board and system manufacturers, connector and semiconductor companies.


    In the course of time, new ideas and suggestions were constantly being added. They all resulted in a thoroughly worked out specification. Since many companies are also involved in other standards (ATCA, VPX etc.), many experiences made there were contributed – even in details that are rather badly solved in these standards and that contributors wanted to make better with CompactPCI Serial.


    The highlights include:


    • Every CPU board can also be used in any peripheral slot (learned from the VMEbus standard).
    • Ethernet is based on xBase-T standards to implement multiprocessing in a simple way (proven in PICMG 2.16).
    • Compatibility of 3U and 6U boards – but without restrictions (learned from mistakes in VME and CompactPCI).
    • Doing without expensive infrastructural assemblies such as MCHs (learned from mistakes in MicroTCA).
    • Split backplane concepts allow easy application-specific wiring (new).
    • Direct connection of front and rear boards without a backplane allows the support of optical connectors (new).
    • Conduction cooling as an integrated component of the specification (new) that allows converting of any board into a conduction-cooled board.

    In a nutshell we may say that – contrary to initial fears and reservations – the cooperation of the individual companies has worked very well. In the case of CompactPCI Serial it was an advantage that the standard was not created out of one product of a company. The products will benefit from this.


    The specification has passed the work group in draft 0.61. The official ballot inside PICMG has already been initiated.

    CompactPCI Serial, CPCI-S.0, has got what it takes to establish CompactPCI as an important standard for modular, robust and inexpensive computers across many markets for the next decade.