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tec.News 17: Kaleidoscope
sub-bus structures, signal functions, timing devices, signal
voltages and master/slave configurations are predetermined.
The default requirements of the VME standard VME64
include a 64-bit data path for boards with 6 rack units
(RU), one 32-bit data path for boards with 3 RU, twice the
bandwidth for data transmission, low noise levels and plugand-play
functions. An upgraded version of this standard
called VME64x also supports hot-swapping. VME64 boards
are compatible with older VME bus systems, so they can also
be used in older VME bus systems and vice versa. VME64
is an expanded version for 64-bit data transmission and
addressing.
A typical transmission consists of an arbitration cycle
(for preservation of the bus control), an address cycle
(for selection of the register) and the actual data cycle.
The process supports read, write, modification and block
transmissions.
(ANSI/VITA 1-1994) interface. These modules are connected
in parallel via a plug connector to the carrier module
(mezzanine modules). All of these I/O modules have a shared
carrier to which various modules are connected in parallel.
The mechanical specification of the carrier module is based
on a VMEbus module with 6 rack units according to ANSI/
VITA specification 1-1994. It is also equipped with two
standard P3 and P4 DIN 41 612 connectors compliant with
VME64 on the front for the I/O field interface. According
to the electrical specifications of VME64, the module
represents a sub-system (a so-called slave) with A16/D16/
D08 (EO) interface on the VMEbus. It receives and controls
The VME bus system is made up of 4 sub-buses: the Data
Transmission Bus, the Arbitration Bus, the Priority Interrupt
Bus and the Utility Bus. The asynchronous data transmission
supports modules with many different response times.
Developed as a flexible environment for a large number
of processor-intensive tasks, the VME bus has evolved
into a widely used protocol in the computer industry. Its
development is based on the IEEE 1014-1987 standard.
HARTING is the connector and backplane
supplier
HARTING India was involved with Omnie right from the
start of the project and later selected as the chosen supplier
of DIN 41 612 connectors, metric cPCI connectors, SEK
Interface connectors and D Sub connectors for high-speed
I/O boards. Subsequently during the project, Omnie also
took the decision to procure the backplanes from HARTING
after close consultation with the end customer. The HARTING
VME64x backplane without P0 connector is a COTS module
in the 6HE format with Automatic Daisy Chain, 12 slots,
screw connections for the mains connection and IP1, IP2,
2P2 plug connectors on the rear with interlocks for secure
connections.
Fig. 1: VME64x Standard Backplane
all of the VME bus signals to P1. The following parameters
can be adjusted with jumpers:
1 Module ID (8-bit)
2 Module address (8-bit)
3 Interrupt (1 of 4)
By contrast, the mechanical specifications of the mezzanine
module are different. The mezzanine module is available in
two sizes:
a) Single width: 110 mm x 24.8 mm, two 16-pole connectors
(in two rows), one of which is a row of male contacts and
one a row of female contacts
b) Double width: 110 mm x 49 mm, four 16-pole connectors,
two of which are rows of male contacts and two are female
contacts
The following I/O modules are used: VMEI2-1, VMEIO20,
VMEIO25 and VMEIO27. The I/O modules have a VME 64
The mezzanine modules receive and generate field signals
via J2 (and J4) connectors and are connected via J1 (and J3)
76 harting tec.News 17 (2009)