© National Instruments Corporation
5-1
VME-MXI-2 User Manual
System Configuration
Chapter
5
This chapter explains important considerations for programming and
configuring a VMEbus/MXIbus system using VME-MXI-2 mainframe
extenders.
Note:
Detailed descriptions of all register bits can be found in Chapter 4, Register
Descriptions.
In a MXIbus system, MXIbus address space is partitioned between
MXIbus devices. A MXIbus device is any device having a MXIbus
interface. MXIbus devices can be VMEbus mainframes, PCs, or
stand-alone instruments. The MXIbus memory map is the same for all
devices in the VMEbus/MXIbus system. You can use a VXIbus
Multiframe Resource Manager (RM) application to configure all
VME-MXI-2 mainframe extenders in the system to partition the
MXIbus address space. If you will not be using a VXIbus Resource
Manager, you will have to configure the Extender LA, A16, A24, and
A32 window registers on all your VME-VXI-2 modules yourself to
allow address mapping in your VMEbus/MXIbus system. If this is the
case, consider “RM” in the remainder of this chapter to be your
application that is configuring the address mapping on the VME-MXI-2
modules.
You can connect a VMEbus/MXIbus system together to form any
arbitrary tree topology. A tree topology has no circular paths.
Figures 5-1 and 5-2 show examples of tree topologies. The system in
Figure 5-1 would not be a tree structure if a cable were added from the
last MXIbus device on Level 1 to the Root PC. Figure 5-2 would also be
an illegal and circular system if a cable were added to connect the two
MXIbus devices on Level 1. At the root of the tree is the multiframe
RM. The root can be a VMEbus mainframe or a stand-alone device, such
as a PC with a MXIbus interface, that can operate as the system RM.
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