National Instruments 370551A-01 用户手册
Glossary
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ACFAIL
A VMEbus backplane signal that is asserted when a power failure has
occurred (either AC line source or power supply malfunction), or if it is
necessary to disable the power supply (such as for a high temperature
condition).
occurred (either AC line source or power supply malfunction), or if it is
necessary to disable the power supply (such as for a high temperature
condition).
address
Character code that identifies a specific location (or series of locations)
in memory.
in memory.
address modifier
One of six signals in the VMEbus specification used by VMEbus masters
to indicate the address space in which a data transfer is to take place.
to indicate the address space in which a data transfer is to take place.
address space
A set of 2
n
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.
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.
address window
A portion of address space that can be accessed from the application
program.
program.
ANSI
American National Standards Institute.
arbitration
A process in which a potential bus master gains control over a
particular bus.
particular bus.
asynchronous
Not synchronized; not controlled by time signals.
B
B
Bytes.
backplane
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.
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.
BERR*
Bus error signal.
binary
A numbering system with a base of 2.
BIOS
Basic Input/Output System. BIOS functions are the fundamental level
of any PC or compatible computer. BIOS functions embody the basic
operations needed for successful use of the computer’s hardware resources.
of any PC or compatible computer. BIOS functions embody the basic
operations needed for successful use of the computer’s hardware resources.