Chapter 6
NI-VXI Configuration Utility
6-14
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VXI/VME Bus Options
Use the options in this group to control features of the VXI/VMEbus
interface on the VXI/VME-MXI-2.
VMEbus System Controller
You can use the System Controller option to override the jumper setting
on the VXI-MXI-2. The VME-MXI-2 does not have an onboard jumper
setting for this option. When the Auto setting (the default setting) is active,
the onboard jumper setting determines if the VXI-MXI-2 is the VXI Slot 0
device. For more information, refer to the
in Chapter 3,
VXI-MXI-2 Configuration and Installation
Otherwise, choose either the Yes or No option. Notice that selecting either
of these options overrides the onboard jumper setting on the VXI-MXI-2,
so it will not matter how the jumper is set. You would need to run the
VXI/VME-MXI-2 Configuration Editor again if you decide to change
the VMEbus System Controller (VXI Slot 0) setting at a later time.
Caution
Do not install a VXI/VME-MXI-2 configured for VMEbus System Controller
(VXI Slot 0) into another slot without first reconfiguring it to either Non-Slot 0
or automatic configuration. Neglecting to do this could damage the VXI/VME-MXI-2, the
VXI/VMEbus backplane, or both.
This means that you should use either the No option or the Auto option. For the
VXI-MXI-2, you also have the option of changing the hardware jumper setting.
VXI/VME Bus Timeout Value
The VXI/VMEbus Bus Timeout (BTO) is a watchdog timer for transfers on
the VMEbus Data Transfer bus. After the specified amount of time has
elapsed, the BTO circuitry terminates a VMEbus cycle if no slave has
responded. The VXI/VME-MXI-2 must provide the VXI/VMEbus BTO
for proper operation because when a MXIbus cycle is involved, the
VXI/VMEbus timeout must be disabled and the MXIbus BTO enabled.
You should disable the BTO of any other BTO module residing in the
mainframe. If this is not possible, set its VXI Bus Timeout option to its
maximum setting to give the MXIbus cycles as much time as possible to
complete.
The lowest value in the allowable range is 15
µ
s and the highest value is
256 ms. The default value is 125
µ
s.
