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Mezzanine Buses

[AMC] [CMC] [EMC] [FMC] [IP] [M-Module] [PC]
[PMC] [PMC-X] [Processor PMC] [PTMC] [VME Info Page] [XMC]
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Mezzanine cards are small form factor cards designed to plug onto larger form factor boards. The definition of Mezzanine is dead on in that it refers to a a low ceiling story between two main stories of a building, sort of a floor x 1/2, which is exactly where this bus sits between a main board and the daughter card. How do you get to be John Malcovich? Take the Mezzanine bus! Sorry.
The bus is a subset or offshoot of the more widely known PCI or ISA Bus.
The larger main boards can be designed to support one or more Mezzanine cards. Not all mezzanine formats are supported by the main boards.
Main cards with a primary function to support mezzanine cards are called carrier cards.
A carrier card contains little or no functionality on-board, but relies on the mezzanine card to add intelligence.
That is a carrier card primarily routes I/O from the mezzanine card, through the carrier card and then out over the backplane.

CMC Description

CMC: Common Mezzanine Card. IEEE 1386 Standard Mechanics for a Common Mezzanine Card Family.
Defines the mechanical specification for the IEEE 1386 series of Mezzanine Cards.
The card size is 74mm x 149mm x 8.2mm (single width) or 149mm x 149mm x 8.3mm (double width).
IEEE1386 uses Board-to-Board 1.00mm (.039") Dual Row connectors.
Mezzanine cards, designed to this standard, can be used interchangeably on a number of Host cards, including;
*VME *VME64 *VME64x *CompactPCI *Multibus I *Multibus II
Additional standards define the board pin out to backplane pin-outs and how the mezzanine maps to the I/O.
However within the CMC standard the connectors are optional and may not all be installed on a mezzanine card.

It appears that the specification was released in 2001, but withdrawn in 2006.
Although the CMC may have come out in the mid 1990's

1386-2001: IEEE Standard for a Common Mezzanine Card (CMC) Family
1386-2001: IEEE Standard Physical and Environmental Layers for PCI Mezzanine Cards (PMC)

Single wide and Double wide Common Mezzanine Card board dimensions

Common Mezzanine Card Dimensions

PC MIP Description

PC MIP: [VITA 29]. Another PCI based mezzanine card introduced in 2001.
Uses the PCI bus specification in a new [board dimension] form factor.
The PCI bus speed must be 33MHz or greater, with a maximum bus width of 33 bits.
Only the 3.3 volt power supply version of PCI is used.
The PC MIP board uses three connectors and two different board sizes.
Single width boards are; 47.50mm x 90.50mm [Type I], or 47.5mm x 99.5mm [Type II].
Double width [dimensions] boards are; 95.00mm x 90.50mm, or 95.00mm x 99.50mm.
Up to six single width cards will fit onto a standard 6U VME card.
However a max of four cards are common with other mezzanine formats.
This form factor uses a front panel. The PC MIP may also be used on desktop PCI cards as well.
The PC MIP specification has been withdrawn and is no longer active.
There do not appear to be any companies producing the form factor.

Single wide and Double wide PC-MIP Mezzanine Card board dimensions

PC-MIP Mezzanine Card Dimensions

Processor PMC Description

Processor PMC: for Processor PCI Mezzanine Cards; VITA 32
The Processor PMC standard provides extensions to the PMC standard [PCI Mezzanine Card] to support CPU based cards. The signaling protocols remains the same between the PMC board and Processor PMC boards. The mechanical format follows the Common Mezzanine Card [CMC] specification [IEEE1386]. However the Processor PMC standards may include changes to the physical and or signaling formats. The Processor PMC board formats follow the size of PMC boards. Two board heights are allowed; 10mm and 20mm high boards. There are several pin functions which change in the Processor PMC specification. The primary purpose of the Processor PMC interface was to enhance the I/O bound functionality of the PMC daughter boards to allow higher order processor functions to be provided. The PCB requires a Bezel to support the front panel opening.

[PPMC Card Manufacturers]

VIM Description

VIM [Velocity Interface Mezzanine]. The bus provides a dedicated data channel of up to 400 MB/sec to each of four processors on a quad processor 6U VMEbus board. Four 160-pin processor node connectors allow peripherals to deliver data directly to the private resources of each processor.
Pentek developed this proprietary bus used on their cards.

Mezzanine related acronyms

AMC: Advanced Mezzanine Card
AdvancedMC: Advanced Mezzanine Card
CMC: Common Mezzanine Card [a mechanical standard]
EMC: I'm still looking. For now use "Excited!", I doubt anyone will call you on it :)
FMC: Confusing. Its from the FPGA standard, so the F could be an acronym for another acronym "FPGA", I'm not even sure that's legal.
IP: IndustryPack
PMC:
PCI Mezzanine Card
M-Module
PC
PMC: A new form factor for the CMC that uses the PCI bus
PMC-X: Revision X of the PMC form factor of the CMC
PPMC: Processor PMC
PrPMC: Processor PMC
PTMC: PCI Telcom Mezzanine Card
XMC: Switched Fabric Mezzanine Card


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