National Instruments VME-SB2020 Getting Started page 55

Glossary
address space
ANSI
B
backplane
block-mode
transfer
BTO unit
bus master
C
C
CLK10
CMOS
Commander
VME-SB2020/NI-VXI/Solaris Getting Started
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.
American National Standards Institute
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.
An uninterrupted transfer of data elements in which the master sources
only the first address at the beginning of the cycle. The slave is then
responsible for incrementing the address on subsequent transfers so that
the next element is transferred to or from the proper storage location. In
VME, the data transfer may have no more than 256 elements; MXI does
not have this restriction.
Bus Timeout Unit; a functional module that times the duration of each
data transfer and terminates the cycle if the duration is excessive. Without
the termination capability of this module, a bus master attempt to access a
nonexistent slave could result in an indefinitely long wait for a slave
response.
A device that is capable of requesting the Data Transfer Bus (DTB) for the
purpose of accessing a slave device.
Celsius
A 10 MHz, ± 100 ppm, individually buffered (to each module slot),
differential ECL system clock that is sourced from Slot 0 and distributed
to Slots 1 through 12 on P2. It is distributed to each slot as a single-
source, single-destination signal with a matched delay of under 8 ns.
Complementary Metal Oxide Semiconductor; a process used in making
chips.
A Message-Based device which is also a bus master and can control one
or more Servants.
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