Advanced Mezzanine Card
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Advanced Mezzanine Cards are printed circuit boards (PCBs) that follow a specification of the PCI Industrial Computers Manufacturers Group (PICMG), with more than 100 companies participating. Known as AdvancedMC™, the official specification designation is AMC.x (see below). AdvancedMC is targeted to requirements for the next generation of "carrier grade" communications equipment. This series of specifications are designed to work on any carrier card (primarlyAdvancedTCA) but also to plug into a backplane directly as defined by MicroTCA specification.
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[edit] AMC specifications
- AMC.0 is the "base" or "core" specification. The AdvancedMC definition alone defines a protocol agnostic connector to connect to a carrier card. Revisions are known as engineering change notices, or ECNs.[1]
- ECN-001 adopted June 2006
- ECN-002 under review (as of September 2006) (expands wireless capabilities, raises power to 80 watts per card)
An AdvancedMC card can use proprietary LVDS-based signalling, or one of the following AMC specifications:
- AMC.1 PCI Express (and PCI Express Advanced Switching) (ratified)
- AMC.2 Gigabit Ethernet and XAUI (under review)
- AMC.3 Storage (ratified)
- AMC.4 Serial RapidIO (under development)
[edit] Sizes
There are four sizes of AMC cards available. A full height (FH) card is the most common, allowing up to 17.91 mm high components. A half height (HH) card allows component heights of up to 11.58 mm. A special carrier card known as hybrid or cutaway carrier is required to hold two half height cards, because the total height exceeds a standard full height and a section of the PCB is removed to make room. Each height is paired with a width, single or double, describing how many carrier slots the board fills. A double width card allows more component space, but does not provide any additional power or bandwidth because it only uses a single connector.
[edit] Connector styles
The pinout of the AMC connector is fairly complex, with up to 170 traces. There are four different lengths the traces can be, which allows hot swapping by knowing in advance which traces will become active in which order upon insertion. To help reduce cost for mass production, a card may only require the traces on one side (pins 1 to 85). The possibility of using only half the pin locations, combined with full and half height combinations, results in four different connector types that are available on the carrier card:
| Connector Style | Pins | Mating Card Type |
|---|---|---|
| B | 85 | One FH card that only needs pins 1-85 |
| B+ | 170 | One FH card that uses all available pins (1-170) |
| AB | 170 | Two HH cards that each only need pins 1-85 |
| A+B+ | 340 | Two HH cards that use all available pins (1-170) |
[edit] MicroTCA (μTCA)
The AdvancedMC card is considered powerful enough that there are situations where the processing functionality is the only requirement. The MicroTCA standard is targeted at supplying a COTS chassis that will allow AMC cards to function without any AdvancedTCA carrier card. On July 6, 2006 MicroTCA R1.0 was approved. Since this approval, multiple companies have launched products.
Versions of MicroTCA with less AdvancedMC card slots are informally known as NanoTCA and PicoTCA.
