PCI PMC

The PCI of PCI PMC
PCI is the acronym for Peripheral Component Interconnect.

The PMC of PCI PMC
PMC stands for PCI Mezzanine Card. Sometimes when people want to refer to a PMC card they call it a PCI PMC card which is a bit redundant.

PCI PMC bus card definitions
When reviewing bus cards, there is a difference between PCI and PMC. PCI bus is an interconnection system between a microprocessor and attached devices supporting expansion slots that are spaced closely for high speed operation.

Now let's look at the PMC of PCI PMC. A PMC is a printed circuit board manufactured to the IEEE P1386.1 standard. This standard combines the electrical characteristics of the PCI bus with the mechanical dimensions of the Common Mezzanine Card or CMC format (another IEEE standard). It enables manufacturers to offer products that are compatible with the well-established PCI bus, but in a smaller and more robust package than standard PCI plug-in cards. The word mezzanine, meaning a platform inserted between two floors of a building, describes the way in which a PMC card fits between two adjacent host cards in a standard card rack, attached to one of the cards by connectors and mounting pillars. A single PMC measures 74 mm x 149 mm. The standard also defines a double-sized card, but this is less common than the single card.

Symmetricom's PCI PMC Card
Symmtricom offers a PCI PMC Card. It is Symmetricom's bc635/637PMC receiver module. This PCI PMC module provides precision time and frequency reference to the host computer system and peripheral data acquisition systems. Time is acquired from either the GPS satellites using a supplied antenna/ receiver (bc637PMC only) or from time code signals, typically IRIG B. Integration of the module is facilitated with optional drivers for Windows 98/NT/2000/XP, Linux Solaris or VxWorks. Central to the operation of the module is a disciplined 10 Mhz oscillator and 100 nanosecond clock. Current time (days to 100 nanoseconds) can be accessed across the PCI bus with zero latency, which allows for very high speed time requests. The oscillator is rate-matched (disciplined) to the input time source and drives the precision 10 MHz frequency output and time code generator circuitry. If time is lost, the module will continue to maintain time (flywheel).