User manual

Chapter 4 VXI-MXI-2/B Configuration and Installation
VXI-MXI-2 User Manual 4-14 © National Instruments Corporation
Configuration EEPROM
The VXI-MXI-2/B has an onboard EEPROM, which stores default
register values that are loaded at power-on. The EEPROM is divided
into two halves—a factory-configuration half, and a user-configuration
half. Both halves were factory configured with the same configuration
values so you can modify the user-configurable half, while the factory-
configured half stores a back-up of the factory settings.
Use switches 1 and 2 of the four-position switch at location U21 to
control the operation of the EEPROM. The Restore Factory
Configuration switch (switch 1) causes the VXI-MXI-2/B to boot off
the factory-configured half instead of the user-modified settings. This is
useful in the event that the user-configured half of the EEPROM
becomes corrupted in such a way that the VXI-MXI-2/B boots to an
unusable state.
The Change Factory Configuration switch (switch 2) lets you change
the factory-default configuration settings by permitting writes to the
factory settings section of the EEPROM. This switch serves as a safety
measure and should not be needed under normal circumstances. When
this switch is off (its default setting) the factory configuration of the
EEPROM is protected, so any writes to the factory area will be ignored.
The factory area is protected regardless of the setting of switch 1.
Figure 4-10 shows the configuration settings for EEPROM operation.
The settings of switches 3 and 4 have no effect on EEPROM
configuration.