Front Panel Features; Vxibus Logical Address - National Instruments MXI-2 Reference Manual

Front Panel Features

VXIbus Logical Address

© National Instruments Corporation
The VXI-MXI-2/B has the following front panel features:
• Three front panel LEDs
– SYSFAIL LED indicates that the VMEbus SYSFAIL line is
asserted.
– MXI LED indicates when the VXI-MXI-2/B is accessed from the
MXIbus.
– VXI LED indicates when the VXI-MXI-2/B is accessed from the
VXIbus.
• MXIbus connector
• Three SMB connectors
– Trigger input
– Trigger output
– External clock
• System reset pushbutton
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/B cannot act as a Resource Manager,
do not configure the VXI-MXI-2/B 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/B does support dynamic configuration of VXI devices within
its chassis, 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/B or the other device so that every device in the system has a
unique associated logical address.
Chapter 6 VXI-MXI-2/B Configuration and Installation
6-3 MXI-2 Configuration Reference Manual