Chapter 2 General Description
© National Instruments Corporation 2-9 VXI-MXI User Manual
• Interrupt Control The interrupt control logic maps the VMEbus
interrupt lines to and from the corresponding
INTX interrupt lines. In conjunction with the
VXI-MXI circuitry, the interrupt requests routed
between VXIbus mainframes through the INTX
connector can be transparently serviced by
interrupt handlers in VXIbus mainframes other
than the mainframe from which the request was
generated. This process takes advantage of
transparent MXIbus interrupt acknowledge cycles.
When an interrupt request received from across
the INTX is driven on the corresponding VMEbus
interrupt line, an interrupt handler in the receiving
VXIbus mainframe generates an interrupt
acknowledge cycle for that interrupt request. This
interrupt acknowledge cycle is transparently
converted into a MXIbus interrupt acknowledge
cycle for that interrupt request level. Similarly,
when a VMEbus interrupt line is driven out of the
VXIbus mainframe across the INTX connection,
an interrupt handler in another VXIbus mainframe
can generate an interrupt acknowledge cycle to
handle that interrupt. The VXI-MXI in the
requesting mainframe recognizes that the MXIbus
interrupt acknowledge cycle is for the request it is
driving and converts the cycle into a VMEbus
interrupt acknowledge cycle that can service the
VMEbus interrupt requester.
• Trigger Control The trigger control logic maps the VXIbus TTL
trigger lines to and from the corresponding INTX
trigger lines.
• System Resets Control The system resets control circuitry maps the
VMEbus signals SYSRESET, SYSFAIL, and
ACFAIL to the corresponding signals on the
INTX connection.
• CLK10 Control The CLK10 control circuitry routes the VMEbus
10 MHz signal to and from the INTX connection.
The configuration of the CLK10 mapping is
controlled by three switches on the INTX
daughter card. Refer to the INTX CLK10
Mapping section of Chapter 3, Configuration and
Installation, for instructions on configuring these
switches.