User manual

Chapter 6 System Configuration
VXI-MXI-2 User Manual 6-40 © National Instruments Corporation
Notice that it is not possible to detect duplicate logical
addresses because devices are found by reading the VXIbus
ID Register. If two devices share a logical address, they will
both respond to an address access without any indication of an
error.
B. For each VXI-MXI-2 found in the mainframe, starting with
the lowest addressed VXI-MXI-2, the RM:
i. Sets the VXI-MXI-2 logical address window to map all of
the logical address space outward and enables the
window.
ii. Scans all logical addresses (0 to FF) in the window,
skipping logical addresses occupied by previously
encountered devices.
iii. For each VXI-MXI-2 found in Step ii, starting with the
lowest addressed VXI-MXI-2, the RM:
a. Sets the VXI-MXI-2 logical address mapping
window to map all of the logical address space
inward and enables the window.
b. Repeats Step 2 recursively.
c. Sets the VXI-MXI-2 inward logical address mapping
window to cover the range up to (but not including)
the VXI-MXI-2 with the next highest logical address
that was found in the logical address space.
iv. Sets the VXI-MXI-2 outward logical address mapping
window to cover the range of the devices connected to
that extender.
Configuring the Logical Address Window Example
This example illustrates how the multiframe RM identifies devices in a
VXIbus/MXIbus system and configures the logical address windows.
The system used is the example VXIbus/MXIbus system shown in
Figure 6-5. Table 6-5 shows the logical addresses we assigned to the
devices in that system before bringing up the system. MXIbus devices
can only be statically configured for the RM to find all devices
connected on a MXIbus link. Therefore, each device must have a
logical address that was configured before system power-up.