It is physically based on Eurocard sizes, mechanicals and connectors DIN , but uses its own signalling system, which Eurocard does not define. It was first developed in and continues to see widespread use today. In , during development of the Motorola CPU, one of their engineers, Jack Kister , decided to set about creating a standardized bus system for based systems. 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 standardization process. At this point, a number of other companies involved in the 's ecosystem agreed to use the standard, including Signetics, Philips, Thomson, and Mostek. The original standard was a bit bus, designed to fit within the existing Eurocard DIN connectors.
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This appendix provides information to help users select third-party VME boards for the Onyx system. The reader may also wish to consult related books such as the following for additional background:. The Onyx board slots have a 9U vertical form factor and measure The board edges must also be less than or equal to 0. If the board is thicker, the edge of the board must be milled to fit into the card guide.
In addition. There are no VME slots in the card cage 1 in either the Onyx system. Table E Both systems also supply approximately 40 watts of 5 V power per VME slot nominally. The card cage 2 also receives approximately to linear feet per minute LFM of air flow.
This assumes the presence of three power boards and one power board. The card cage 3 also receives approximately to LFM of air flow through the chassis. If a VME board requires more than the normal slot power allotment approximately 40 watts of 5 V power per slot in CC2 or greater than 70 watts in a card cage 3 , the board still can be used.
However, the user needs to ensure that the board has the proper air flow for cooling purposes and sufficient available power. To help maintain proper cooling according to manufacturer's specifications , the board may need special custom baffles or a set of non-component, enclosure boards to surround the VME board with sufficient air flow.
In addition, a third-party VME board that requires more than the normal VME slot power can be used, as long the following conditions are met. The board uses all three "P" connectors on the system backplane, the P1, P2, and P3. However, as a result, you could not install any additional VME boards, since the VME power allotment would already be saturated.
In the CC3, you can install up to six watt boards, ssuming that all potential power boards three and one are installed. However, as a result, the remaining VME slots cannot then be used. Generally, there are VME boards or devices that should not be integrated into the Onyx system.
This section provides guidelines for selecting or designing third-party VME board. While in VME Master mode, devices must only access the system memory using Nonprivileged data access or Nonprivileged block transfers. Devices must have the ability to be configured so that their address range does not conflict with those used by the Onyx system. The device should also be able to respond to addresses generated by the system.
Be sure to place boards starting in the first VME slot, or jumper the daisy-chained signals across the empty slots. Otherwise, this will break the interrupt acknowledge and bus arbitration schemes. Metal face plates or front panels on VME boards may need to be removed.
Data lines. Address lines. Address modifier lines. Address strobe. Appendix E. VME bus Implementation. Warning: All board installations or removals should be performed only by personnel certified by Silicon Graphics. Unauthorized access to the card cage area could result in system damage, or possible bodily harm, and could void the warranty for the system.
General Information. Board Dimensions. Rackmount VME Issues. Note: These custom air flow devices will need to be supplied by the customer. The board does not draw more than the amount of power for allocated for VME board use. The board does not exceed the power rating for the VME pins. Special VME Considerations. Caution: Be sure to observe these general rules to avoid possible damage to the VMEbus and system. Devices should require 8-bit interrupt vectors only. Devices must not require UAT unaligned transfers or tri-byte access from the Onyx system.
The Onyx system does not support VSBbus boards. However, the Onyx chassis already provides sufficient shielding for boards inside the chassis, so these plates are not necessary.
VME Pins. Note: No connections are made to rows A and C of connector P2. These lines are not bussed across the backplane. The P3 connector uses the Sun power convention. A00 through A31 Address lines. AM0 through AM5 Address modifier lines. AS Address strobe. BR0 through BR3 Bus request lines. BBSY Busy busy. BCLR Bus clear. IACK Interrupt acknowledge. Does not control bus timing. BERR Bus error line. Configuring a Multipipe Onyx System. Data Strobe lines. Interrupt acknowledge.
Data transfer acknowledge.
ISBN 13: 9781885731081
The VMEbus Handbook, Fourth Ed.