QMC Overview

The VITA 93 standard, referred to as QMC, defines a Small Form Factor mezzanine that is significantly smaller than XMC with both host and I/O interface connectors. The host interface supports modern high-speed serial fabrics. Multiple modules can be installed on various carrier card form factors including 3U/6U Eurocards (VPX, cPCI, VME, etc.), VNX+, PCIe expansion cards, and others. It is suitable for deployment in commercial, industrial, space, or military grade rugged environments with air-cooled or conduction-cooled formats.

The VITA 93.1 standard defines the mechanical details of two mezzanine cards with front-panel I/O. These complement the VITA 93.0 QMC Standard. QMC-XIOm defines a connection to the VITA 93 carrier card's IO connector. QMC-SIOm defines a connection to a carrier card’s smart host connector.  These I/O cards are intended to be used on carrier cards or rear transition modules to break out the QMC I/O signals to industry standard connectors that fit through the carrier card’s face plate or rear transition module panels.

QMC addresses the need in the market for a small form factor I/O mezzanine.  Its function is much the same as the earlier IP Module [VITA 4.0], PMC [IEEE 1386] and XMC [VITA 42.0], [VITA 61.0], [VITA 88.0] mezzanine card standards in that it provides connectors and interfaces for both the Carrier-side connector as well as the I/O-side, but in a much smaller form factor.  The emergence of the VNX+ standard [VITA 90.0] drove the initial need for a smaller form factor mezzanine with backplane I/O capability, but it was soon realized that this new form factor would have significant utility across many form factors and deployed environments.

QMC is designed for both performance and flexibility in that it supports high-speed serial data links through its defined Carrier interface, along with its user-defined I/O interface.  QMC was designed specifically to support a range of carrier card formats with varied deployed environments and supporting both air- and conduction cooled designs.

The QMC standard consists of four elements.  Two of these elements: The QMC mezzanine module, and the QMC Carrier.  Future planned standard documents will address the other two: The SIOm and the XIOm faceplate I/O extension modules.

Objectives

QMC defines an open standard for small form factor mezzanine cards.  This document grew out of the earlier “Small Form Factor Mezzanine Study Group” that identified the basic form factor, connectors, and many of the initial technical details of the standard. 

• The goals for this standard include: Significantly smaller than XMC (specifically to be accommodated on the new VITA 90 VNX+ 19mm form factor)
• Providing two interfaces
• • A Carrier-side / primary interface, supporting PCIe speeds beyond Gen2 (the current limit of Mini PCIe)
  • An I/O / secondary interface, to support either front-panel or backplane I/O (similar in function to the XMC P16 connector)
• Able to be used on a range of carrier cards (3U/6U Eurocards, VNX+, PCIe edge connector cards, etc.)
• Able to be deployed in either commercial, industrial, or military-grade rugged environments.

The QMC standard, therefore, specifies the mechanical, electrical, protocol, and general cooling requirements of QMC modules and carriers.

Architecture

Example Carrier/QMC Architecture

This illustration shows the VITA 93 architecture, consisting of:

1. A Carrier-based PCI-Express “switching entity” that provides local PCI-Express ports to the various VITA 93 devices, more specifically QMCs and SIOms.  The “switching entity” bridges between the outside world (Ethernet, upstream PCI-Express, Power, IPMB) and the local PCI-Express ports.
2. One or more QMCs that connect the PCI-Express ports of the “switching entity” to application I/O.
3. A Carrier-defined “Connection Matrix” that connects the IOPIPEs emanating from installed QMCs to various Carrier I/O resources, such as local connectors, front panel connectors, backplane connections, and XIOm “Connector boards”.