National Instruments VXI-MXI User Manual page 191

Glossary
Address Modifier
Address Space
Address Strobe
Address Window
ANSI
Arbiter
Arbitration
Asynchronous
Asynchronous
Protocol
B
B
Backplane
Base Address
BERR*
Bit
Block Data Rate
VXI-MXI User Manual
One of six signals in the VMEbus specification used by VMEbus masters
to indicate the address space and mode (supervisory/nonprivileged, data/
program/block) in which a data transfer is to take place.
n
A set of 2 memory locations differentiated from other such sets in
VXI/VMEbus systems by six addressing lines known as address
modifiers. n is the number of address lines required to uniquely specify a
byte location in a given space. Valid numbers for n are 16, 24, and 32. In
VME/VXI, because there are six address modifiers, there are 64 possible
address spaces.
A VMEbus or MXIbus signal used to indicate that valid addressing
information exists and may be decoded.
A portion of address space that can be accessed from the application
program.
American National Standards Institute
Circuitry providing the bus arbitration mechanism for a system.
A process in which a potential bus master gains control of a bus.
Not synchronized; not controlled by time signals.
A two-device, two-line handshake trigger protocol using two consecutive
even/odd trigger lines (a source/acceptor line and an acknowledge line).
Bytes
An assembly, typically a printed circuit board, with 96-pin connectors and
signal paths that bus the connector pins. A C-size VXIbus system will
have two sets of bused connectors called J1 and J2. A D-size VXIbus
system will have three sets of bused connectors called J1, J2, and J3.
A specified address that is combined with a relative address to determine
the absolute address of a data location. All VXI address windows have an
associated base address for their assigned VXI address spaces.
Bus Error signal. This signal is asserted by either a slave device or the
BTO unit when an incorrect transfer is made on the Data Transfer Bus
(DTB). The BERR* signal is also used in VXI for certain protocol
implementations such as writes to a full Signal register and
synchronization under the Fast Handshake Word Serial Protocol.
Binary digit. The smallest possible unit of data: a two-state, yes/no, 0/1
alternative. The building block of binary coding and numbering systems.
Eight bits make up a byte.
Transfer rate when using MXIbus block-mode transfers.
Glossary-2 © National Instruments Corporation