1 Answers
A PCI Mezzanine Card or PMC is a printed circuit board assembly manufactured to the IEEE P1386.1 standard. This standard combines the electrical characteristics of the PCI bus with the mechanical dimensions of the Common Mezzanine Card or CMC format.
A mezzanine connector connects two parallel printed circuit boards in a stacking configuration. Many mezzanine connector styles are commercially available for this purpose, however PMC mezzanine applications usually use the 1.0 mm pitch 64 pin connector described in IEEE 1386.
A PMC can have up to four 64-pin bus connectors. The first two are used for 32 bit PCI signals, a third is needed for 64 bit PCI signals. An additional bus connector can be used for non-specified I/O signals. In addition, arbitrary connectors can be supplied on the front panel of the chassis or case; also known as a "bezel".
The PMC standard defines which connector pins are used for which PCI signals; in addition it defines the optional 64 "P4" connector pins for use of arbitrary I/O signals.