Chapter 3 VXI-MXI-2 Configuration and Installation
VXI/VME-PCI8022 for Solaris 3-4
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National Instruments Corporation
VXIbus Logical Address
Each device in a VXIbus/MXIbus system is assigned a unique number
between 0 and 254. This 8-bit number, called the logical address,
defines the base address for the VXI configuration registers located on
the device. With unique logical addresses, each VXIbus device in the
system is assigned 64 bytes of configuration space in the upper 16 KB
of A16 space.
Logical address 0 is reserved for the Resource Manager in the VXIbus
system. Because the VXI-MXI-2 cannot act as a Resource Manager, do
not configure the VXI-MXI-2 with a logical address of 0.
Some VXIbus devices have dynamically configurable logical
addresses. These devices have an initial logical address of hex FF or
255, which indicates that they can be dynamically configured. While
the VXI-MXI-2 does support dynamic configuration of VXI devices
within its mainframe, it is itself a statically configured device and is
preset at the factory with a VXI logical address of 1.
Ensure that no other statically configurable VXIbus devices have a
logical address of 1. If they do, change the logical address setting of
either the VXI-MXI-2 or the other device so that every device in the
system has a unique associated logical address.
You can change the logical address of the VXI-MXI-2 by changing the
setting of the 8-bit DIP switch labeled LOGICAL ADDRESS SWITCH
(location designator U43) on the panel. The down position of the DIP
switch corresponds to a logic value of 0 and the up position corresponds
to a logic value of 1. Verify that the VXI-MXI-2 does not have the same
logical address as any other statically configured VXIbus device in your
system. Remember that logical addresses hex 0 and FF are not allowed
for the VXI-MXI-2. Also, when setting logical addresses, keep in mind
the grouping requirements set by the system hierarchy. See VXI-6,
VXIbus Mainframe Extender Specification, for more information on
setting logical addresses on a multimainframe hierarchy.