Advanced Mezzanine Card

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.

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. Intermediate revisions are known as engineering change notices, or ECNs.

R1.0 adopted January 3, 2005

ECN-001 adopted June 2006

R2.0 adopted November 15, 2006

An AdvancedMC card can use proprietary LVDS-based signaling, 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)

Sizes

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.

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 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:

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

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.

External links

• Official PICMG Site
• Integrated, Low-Cost MicroTCA Platforms
• THE CUBE, a microTCA development system
• The MicroTCA Summit
• coreIPM Project: Free & Open Source firmware for AMC Platform Management
• NGN packet processing system using Octeon
• IPM430 CoreIPM firmware ported to TI MSP430. (open source)