PCI mezzanine card
The PCI Mezzanine Card ( PMC ) is a circuit board that complies with the IEEE 1386.1 specification . It is a form factor for daughter cards , usually with input and output functions .
The PCI mezzanine card combines the common mezzanine card (CMC) specified in IEEE 1386 with the PCI bus as an electrical interface. The printed circuit board is 149 × 74 mm in size. A double PCI mezzanine card is also defined, but this is rarely used. A front plate (bezel) is attached to one of the front sides of the board, which can accommodate connectors for I / O signals. The opposite side is occupied by up to four 64-pin connectors (P1 to P4). Two of these connectors accept the PCI bus (P1 & P2), which can be expanded from 32-bit to 64-bit with P3. The fourth connector P4 is available for module-specific I / O signals that can be made available via the backplane . The signal voltage for the PCI bus (5 V or 3.3 V) is determined by a coding pin on the carrier card; Depending on the model, some PMCs accept both voltages or only one of them.
A PMC is plugged onto a carrier card as a daughter card and is then parallel to this and the neighboring card (hence the name: mezzanine = mezzanine). VMEbus or CompactPCI cards are the most common carrier cards. A PMC fits on a Europe card ( e.g. 3 U CompactPCI cards); Double Euro cards ( e.g. in 6 U VMEbus format) offer space for up to three PMCs.
The connection of PMCs and carrier cards enables flexible and modular systems to be set up that can be easily expanded and converted. There are PMCs for all possible areas of application, for example Ethernet , digital I / O, A / D / D / A or graphics cards or other special applications.
variants
The PMC specification has experienced various extensions and variants. Essentially, these are adaptations of the circuit board mechanics to special requirements or the addition of new interfaces. Most of the extensions have been defined by VITA :
- VITA 20: CCPMC - Conduction Cooled PMC . Defines a PMC with special connection surfaces for heat sinks , which allow the PMC to be operated in closed housings without further cooling measures.
- VITA 32: Processor PMC . Defines an extension of the PMC standard that allows a processor PMC to work as a master CPU in a system.
- VITA 35: For PMC-P4 Pin Out Mapping to VME-P0 and VME64x-P2 . Defines a pin mapping of the PMC back-I / O via P4 for VMEbus cards
- VITA 39: PCI-X for PMC and Processor PMC . Extends the PCI bus of the PMC by PCI-X .
- VITA 42.0: XMC . Extends the PMC standard by an additional connector via which various high-speed protocols such as RapidIO , PCI Express or HyperTransport can be used.
The PICMG has also specified a pin mapping of the PMC back I / O via P4 for Compact PCI (PMC I / O, PICMG 2.3), as well as an extension of the PMC by various telecommunications standards (PTMC, PICMG 2.15).