PICMG Releases New Specification: CompactPCI Serial R3
April 30, 2025
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In a recent announcement, PICMG, a consortium to develop innovative open standards in embedded computing, made public its CompactPCI Serial Revision 3 (CPCI-S.0 R3.0).
This is the third revision of the standard, and the organization said it’s intended to ensure future viability and scalability. CompactPCI Serial was originally developed as an extension of the open CompactPCI standard to meet the demand for robust, modular and powerful computer systems in industrial and embedded applications.
The combination of high performance, modularity and robustness has made CompactPCI Serial a popular standard for industrial applications, automation, and any use case that requires robustness, interoperability and resilience to harsh environments with comprehensive connectivity.
CompactPCI supports serial data transfer rates via PCI Express, USB, and Ethernet, a robust design with AirMax connectors and full interchangeability with CompactPCI cards via 3U/6U slot card systems. Developers can look forward to the completely new opportunities offered by revision 3, which include:
- Full PCI Express (PCIe) support: While R2 supported PCI Express up to Gen3 with 8 GT/s, R3 extends support to PCI Express Gen4 with 16 GT/s, which means increasing speed by doubling the data rate.
- USB support: USB interface support has been increased from USB 3.0 (Gen1) with 5 Gb/s in R2 to USB 3.1 (Gen2) with 10 Gb/s in R3, doubling the bandwidth.
- Ethernet: R3 introduces support for 10GBASE-T and 10GBASE-KR Ethernet, enabling higher bandwidth network speeds.
- Connectors: In order to realize these higher data rates, new AirMax VSe high-speed connectors for CPU boards are used in R3 instead of AirMax VS in Release 2. These connectors are fully upwards and downwards compatible.
“I am very proud that with Revision 3 of the specification, we have managed to provide all embedded integrators with better CompactPCI Serial performance. Developers can look forward to better connectivity, higher performance and much better scalability,” said Jess Isquith, President of PICMG.
The CompactPCI specification defines a modular computer system, consisting of a backplane, a system slot, and up to 24 peripheral boards. The mechanical design is fully backward compatible to CompactPCI and will interoperate with existing systems. A system slot board can be used in a peripheral slot as well to do multiprocessing. The easiest way to communicate in this case is via Ethernet. Ethernet uses cable standards ‘xxBase-T’ instead of dedicated backplane standards. This lowers the cost, guarantees better interoperability and offers currently up to 10 Gb/s data throughput. Plus, implementation of the Ethernet connection of a system board can be done with a mezzanine board (3U or 6U). Due to this concept, more flexibility will be achieved, because the usage of Ethernet does not depend on the system board itself.
CompactPCI Serial can be combined with existing CompactPCI boards by using a CompactPCI PlusIO system slot card. These hybrid systems offer an ideal migration path from parallel to serial connections. CompactPCI Serial for Space specifically addresses the extreme environment requirements for outer space. Developers who want to build applications for harsh environments in industry, aviation or more can now download the new specification from the PICMG website and start designing immediately. PICMG member companies are also already working on their first products based on the new specification.
Additional material can be found here: https://www.picmg.org/openstandards/compactpci-serial/
Revision 3 of CompactPCI Serial can be downloaded here: https://www.picmg.org/product/compactpciserial-specification-r3/
Ken Briodagh is a writer and editor with two decades of experience under his belt. He is in love with technology and if he had his druthers, he would beta test everything from shoe phones to flying cars. In previous lives, he’s been a short order cook, telemarketer, medical supply technician, mover of the bodies at a funeral home, pirate, poet, partial alliterist, parent, partner and pretender to various thrones. Most of his exploits are either exaggerated or blatantly false.
