Glossary
PCI-Based MXI-2 Interface for Windows G-4 ni.com
DMA Direct Memory Access; a method by which data is transferred between
devices and internal memory without intervention of the central
processing unit
DRAM Dynamic RAM (Random AccessMemory); storage that the computer must
refresh at frequent intervals
driver window A region of PCI address space that is decoded by the PCI-MXI-2,
PCI-MXI-2 Universal, or PXI-8320 for use by the NI-VXI software
DTB See Data Transfer Bus.
dynamic configuration A method of automatically assigning logical addresses to VXIbus devices
at system startup or other configuration times
dynamically configured
device
A device that has its logical address assigned by the Resource Manager.
AVXI device initially responds at Logical Address 255 when its MODID
line is asserted. A MXIbus device responds at Logical Address 255 during
a priorityselect cycle.The Resource Manager subsequentlyassigns it anew
logical address, which the device responds to until powered down.
E
ECL Emitter-Coupled Logic
EEPROM Electronically Erasable Programmable Read Only Memory
embedded controller An intelligent CPU (controller) interface plugged directly into the VXI
backplane, giving it direct access to the VXIbus. It must have all of its
required VXI interface capabilities built in.
expansion ROM An onboard EEPROM that may contain device-specific initialization and
system boot functionality
external controller In this configuration, a plug-in interface board in a computer is connected
to the VXI mainframe via one or more VXIbus extended controllers. The
computer then exerts overall control over VXIbus system operations.
F
fair requester A MXIbus master that will not arbitrate for the MXIbus after releasing it
until it detects the bus request signal inactive. This ensures that all
requesting devices will be granted use of the bus.
