VMEbus is a computer bus standard originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications. It is physically based on the Eurocard sizes, mechanicals and connectors, but uses its own signalling system, which Eurocard does not define. It was first developed in 1981, and continues to see widespread used today.
History
In 1979 Motorola were developing their new 68000 CPU, and one of their engineers, Jack Kister, desided to set about creating a standardized bus system for 68000-based systems, which he called VERSAbus. He was later joined by John Black, who refined the specifications and created the VERSAmodule product concept. Sven Rau and Max Loesel of Motorola-Europe added a mechanical specification to the system, basing it on the Eurocard standard that was then late in the standarization process. The result was first known as VERSAbus-E, but was later renamed to VMEbus, for VERSAmodule Eurocard bus. A number of other companies involved in the 68000's ecosystem agreed to use the standard, and soon it was being officially standardized by the IEC.
The original standard was a 16-bit bus, designed to fit within the existing Eurocard DIN connectors. However there have been several updates to the system to allow wide bus widths, and the current VME64 includes a full 64-bit bus in a 6U sized card, and 32-bit for 3U cards. Other associated standards have added live-insertion handling (plug-n-play), smaller cards known as IP's that plug into a single VMEbus card, and various interconnect standards for linking VME systems together.
Description
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