This is an easy to read book that covers the VMEbus and VXIbus specifications, graphics, disk interfaces, Ethernet, image processing and interfacing to external. The input to the PID-controller is the commanded propeller revolution from the VME rack and the measured propeller revolution from the tachometer. Devan, Steve. Discussion of factors to be considered in selecting desktop publishing software for the Macintosh microcomputer focuses on the two approaches to such software, i. BSP Organization.
This chapter is a general discussion of the issues and not an. Last edited by Mamuro. MC VMebus master board. Chun Cheong Mak. Written in English Edition Notes M. Share this book. Wessex building price book. Foreman training methods. Martin Scorseses Raging bull. The geography of the globe. Disgaea Novel. Remnants of the Later Syriac Versions of the Bible.
Complete and progressive vocal exercises Bartending inside-out. The protocol allows VME compatible modules to interact at much higher speeds. VMEbus has the largest software base of any computer architecture. That's quite a claim, but it is supported by the fact that there are over known, commercial operating systems running on VMEbus.
Other, proprietary operating systems are also known to exist. Table 2 shows just a few examples. VMEbus is quite fast, especially in it's most recent manifestations. In fact, it is arguably the fastest of all of the popular microcomputer buses, and certainly the fastest among the 'big commercial backplane buses' i.
Table 3 shows the typical, maximum data transfer speeds that can be achieved between VMEbus modules. The actual data transfer rate of a VMEbus module may be slower than that shown in the Table. The user is advised to contact the board manufacturer for more details. Furthermore, we'll use the nomenclature that's used in the standard s. The VMEbus architecture is generally described using a concept of functional modules. These functional modules are a conceptual tool.
However, in some cases they also describe actual hardware. Table 4 describes all of the functional modules available on VMEbus. The various functional modules communicate with each other over the five sub-buses shown in Table 5.
The sub-buses are also a conceptual tool, and are often used in conjunction with each other. Bus cycles are impressed upon the sub-buses. There are other bus cycles that are more specialized, or allow faster operation. These are summarized in Table 6. The VMEbus specification allows different address and data widths to be used based on an application requirement. While all combinations are possible, certain combinations are more common than others.
As stated earlier A24 is usually found only on older 6U modules and is quickly being replaced by A This is possible because VMEbus uses something called address modifier codes to 'tag' each bus cycle. As new cycles are developed, they are tagged with a new address modifier code, thereby insuring compatibility between modules.
Future bus cycles are also planned. The VMEbus specification allows full peer-to-peer multiprocessor capabilities. This is done with a flexible bus arbitration scheme that allows up to 21 masters in each system. A central bus arbiter, which is located in the first slot in the backplane and is part of the VMEbus system controller , determines which master may use the bus. Arbitration methods include priority, round-robin and other scheduling algorithms.
There are two mechanical form factors for VMEbus modules. These are called single and double height modules.
Traditionally, these modules can generate or accept up to bit address and bit data transfers. Single height modules are commonly used if space is limited. Because of their size, they are also more resilient to shock and vibration than double height boards. The larger and more popular size VMEbus board is the double height module. Traditionally, 6U modules can generate or accept up to bit address and bit data transfers.
Single and double height modules are sometimes referred to as 3U and 6U boards. The 'U' is a unit of measure for the front panel, where each 'U' is equal to 1. This specification shows the dimensions for a variety of board sizes up to 12U x mm , as well as sub-racks and other enclosures.
Furthermore, the VME64x standard allows the use of a rear transition module. The rear transition module cards are defined by the IEEE Some manufacturers also offer triple height 9U boards. Strictly speaking, these modules are not supported by the VME64 specification.
However, some users choose to mount 3U, 6U and 9U boards into a single sub-rack. Most Eurocard packaging systems will support multiple card sizes in a single chassis. For example, an adapter can be used to install a 6U board into a 9U card slot. It is called the VITA 1. The use of two standard card sizes has proven to be one of the biggest features of VMEbus.
Users that have the space can go with the larger and more popular 6U card. VMEbus backplanes are available in lengths between one and twenty-one slots. On standard backplanes, boards are located on 0. There are three general types of backplanes available:. Each of these styles of backplanes are available in 3U and 6U form factors.
Furthermore, there are many options available on VMEbus backplanes. Some of the more popular options include:. The maximum size of all VMEbus backplanes is 21 slots 19" width. The fundamental limits on the maximum length are how much drive current is available on each of the VMEbus boards, and the time delay down the backplane.
If more slots are needed, there are generally two ways to handle the problem: 1 use a VMEbus-to-VMEbus bridge card set or 2 use a pair of 'reflective memory' cards. The bus-to-bus bridges essentially allow bus cycles on one backplane to appear on another. The reflective memory cards allow a memory segment on one backplane to appear on another.
There are several vendors for each of these types of products. Another popular VMEbus card style is the conduction cooled module. These are used mainly in military and aerospace applications where convection cooling cannot be used. These allow heat to conduct through the printed circuit board or through a conduction plate on the backside.
Special expanding card guides then transfer the heat through rails and then out to the chassis. These connectors are very reliable, are low cost, and are available from a variety of suppliers. The pin connector has thirty-two additional pins located on both sides of the original DIN connector. These are designated as the 'z' and 'd' rows. The new connector was added for two reasons:.
Four pre-charge pins are provided on the new connector. These form a make-first, break-last connection. This feature is intended for hot-swap boards, and are used to pre-charge bus interface circuitry. The pin connector is completely optional in the VME64 standard. The connector itself is not needed to support any of the newly defined functions.
For example, it is not needed to support the new sixty-four bit address and data cycles. The pin connector is designed to allow full forward and backward compatibility: older legacy boards will fit into new backplanes and vice-versa.
This is especially true in military and telecom applications. For example, in many applications the use of front panel cables are frowned upon because:. These connectors are available from AMP Inc. Unlike the DIN connector family, they include specifications for mating impedance and maximum capacitance.
This makes them an excellent choice for high speed signals. For example, a coaxial cable or fiber-optic connector could be used. This practice is not recommended, as the board may not be compliant with VME64x backplanes.
However, if a custom connector must be used, then the VME64x standard recommends that the front panel keying mechanism be installed to prevent installation of an incompatible module. Mezzanine modules are a popular way to customize a VMEbus card. These cards generally fit on top of a common base board. The mezzanine modules have become very popular in recent years.
That's because they save a great deal of hardware development time, and inventory. Software development is also faster and less expensive. While the mezzanine module concept has been around for many years, the VMEbus mezzanine industry has been fragmented because of all of the types of mezzanine cards. This situation has improved steadily as new standards have been adopted.
There is currently a plethora of mezzanine standards that are available. Currently, there are over 30 types available for VMEbus modules. However, two types of mezzanine modules seem to be gaining a substantial foothold. Copies of the VMEbus specifications are available from a variety of sources. That's because VMEbus has undergone various revisions through different organizations. Obsolete VMEbus equipment new or used can be obtained from a variety of sources, including the following firms note: these firms are not VITA members and this list is provided for convenience only :.
Online auction houses such as ebay very often have used VMEbus equipment for sale. All rights reserved. Critical Embedded Systems are everywhere. Forgot password. Members Only Join.
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Technology Roadmaps. VITA Personas. FMC Information. Reports and White Papers. Embedded Tech Trends. Why was VMEbus created in the first place? What are the general VMEbus features? What is VMEbus used for? What was the 'original' VMEbus standard? What software runs on VMEbus computers? How fast is VMEbus? How does it work? What are address modifier codes? What are the various address and data size capabilities?
What are the bus grant and interrupt acknowledge chains? Can it support multiple bus masters arbitration? What is the slot 1 system controller? What is metastability? Why is it important to VMEbus board designers? What type of mechanical hardware does VMEbus use? What styles of backplanes are available? What if I need more than 21 slots in a backplane i. Can I get conduction cooled hardware? What's the difference between the pin and pin connectors? Are the two styles of connectors compatible?
What is a mezzanine module?
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