PICMG approves new CompactPCI Express spec
PCI Industrial Computer Manufacturers Group (PICMG) —a consortium of 400-plus companies collaboratively developing open specifications for high-performance telecom and industrial computing applications—has recently released the CompactPCI Express Specification denoted EXP.0. [PCI, in turn, stands for peripheral component interconnect.] The new spec brings PCI Express technology to the popular PICMG 2.0 CompactPCI (cPCI) form factor, while maintaining compatibility with cPCI hardware and software, according to the consortium. More than 40 companies participated in developing CompactPCI Express specification.
Objective of the specification is to meet future needs of the CompactPCI, PXI, military, and aerospace markets. CompactPCI Express offers a migration path for users of cPCI form factor who want the added performance of PCI Express. CompactPCI Express defines connector, electrical, and mechanical requirements of 3U/6U system boards, peripheral boards (type 1 and 2), switch boards, and backplanes. (Type 1 peripheral and system boards have the same pin definitions, allowing a CPU board to be designed to work in both slot types. Type 2 peripheral boards can be used in type 1, type 2, and hybrid slots. Switch boards provide a modular way to provide PCI Express fan out.)
The specification defines the system slot and board to have up to 24 lanes and up to four links of PCI Express for up to 6 GB/s system bandwidth per direction. Type 1 peripheral slots and boards can have up to 16 lanes of PCI Express for up to 4 GB/s bandwidth per direction; Type 2 peripheral slots are specified for up to 8 lanes of PCI Express for up to 2 GB/s.
'CompactPCI Express leverages the Advanced Differential Fabric (ADF) connector used by AdvantedTCA to carry the PCI Express Signals,' says Mark Wetzel of National Instruments and EXP.0 subcommittee chair. 'The specification maintains hardware compatibility with CompactPCI by allowing backplanes to have CompactPCI slots as well as hybrid slots, which
support CompactPCI, PXI, and Compact PCI Express peripheral boards.'
The complete specification is available to PICMG members and can be purchased by non-members. For more information on new PICMG developments, visit www.picmg.org/picmgnewinitiatives.stm .
The trend continues the capabilities expansion of previous form factors. For related news from Control Engineering, see also “ PXI takes the Express. ”
Frank J. Bartos, executive editor, Control Engineering