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Chapter 3      Software Overview
© National Instruments Corporation
3-67
NI-VXI User Manual
  
VXI/VMEbus Extender Functions
The NI-VXI software interface fully supports the standard VXIbus
extension method presented in the VXIbus Mainframe Extender
Specification
. When the National Instruments Resource Manager (RM)
completes its configuration, all default transparent extensions are
complete. The transparent extensions include extensions of VXI/VME
interrupt, TTL trigger, ECL trigger, Sysfail, ACfail, and Sysreset
signals. The VXI/VMEbus extender functions are used to dynamically
change the default RM settings if the application has such a
requirement. Usually, the application never needs to change the default
settings. Consult your utilities manual on how to use the NI-VXI
resource editor utility, either 
VXIedit
 or 
VXItedit
, to change the
default extender settings.
Note:
The MXIbus, which is used as the transparent mainframe extender bus,
extends both VXI and VME chassis and even allows a system consisting
of both VXI and VME chassis.
The following paragraphs describe the VXI/VMEbus extender
functions. The descriptions are presented at a functional level
describing the operation of each of the functions.
  MapECLtrig
MapECLtrig
 configures mainframe extender triggering hardware to
map the specified ECL triggers for the specified mainframe in the
specified direction (into or out of the mainframe). If the specified
frame extender can extend VXI ECL triggers between the mainframes,
you can use 
MapECLtrig
 to configure the mainframe-to-mainframe
mapping. The NI-VXI Resource Manager automatically configures a
default mapping based on the user-modifiable configuration files. The
MapECLtrig
 function can dynamically reconfigure the ECL trigger
mapping. Only special circumstances should require any changes to the
default configuration.
  MapTTLtrig
MapTTLtrig
 configures mainframe extender triggering hardware to
map the specified TTL triggers for the specified mainframe in the
specified direction (into or out of the mainframe). If the specified
frame extender can extend VXI TTL triggers between the mainframes,