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 (primarily AdvancedTCA) but also to plug into a backplane directly as defined by MicroTCA specification.
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An AdvancedMC card can use proprietary LVDS-based signaling, or one of the following AMC specifications:
There are six types of AMC cards ("Module") available. A Full-size Module is the most common, allowing up to 23.25 mm high components (from centerline of PCB). A Mid-size Module allows component heights maxed at 11.65 to 14.01 mm (depending on board location). A Compact Module allows only 8.18 mm. A special carrier card known as hybrid or cutaway carrier is required to hold one Full-size Module or two Compact-size (see connectors below). 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.
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 various height combinations, results in four different connector types that are available on the carrier card:
| Connector Style | Pins | Mating Card Type |
|---|---|---|
| B | 85 | One module that only needs pins 1-85 |
| B+ | 170 | One module card that uses all available pins (1-170) |
| AB | 170 | Two adjacent modules that each only need pins 1-85 |
| A+B+ | 340 | Two adjacent modules that use all available pins (1-170) |
Bay sizes:[2]
| Bay | Aperture | Connector | Compact Module | Mid-size Module | Full-size Module |
|---|---|---|---|---|---|
| Compact Conventional Bay | 3 | B, B+ | Slot B | - | - |
| Mid-size Conventional Bay | 4 | B, B+ | Convert face plate to mid-size | Slot B | - |
| Single Slot Cutaway Bay | 6 | B, B+ | Convert face plate to full-size | Convert face plate to full-size | Slot B |
| Dual Slot Cutaway Bay | 6 | AB, A+B+ | Slots A and B | Convert face plate to full-size | Slot B |
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. The function of the ATCA carrier board and of the ATCA shelf manager are concentrated on one board, which is called the MicroTCA Carrier Hub (MCH). On July 6, 2006 MicroTCA R1.0 was approved. Since this approval, companies like Advantech, Kontron, N.A.T., and others, have launched AMC and MCH products.
Versions of MicroTCA with fewer AdvancedMC card slots are informally known as NanoTCA and PicoTCA.