Chapter 1
Introduction
VME-MXI-2 User Manual
1-2
© National Instruments Corporation
MXI-2 Description
MXI-2 is the second generation of the National Instruments MXIbus
product line. The MXIbus is a general-purpose, 32-bit, multimaster
system bus on a cable. MXI-2 expands the number of signals on a
standard MXI cable by including all VMEbus interrupts, VXIbus
triggers, VXIbus CLK10, and all of the VMEbus utility bus signals
(SYSFAIL*, SYSRESET*, and ACFAIL*).
Because MXI-2 incorporates all of these new signals into a single
connector, the standard VME-MXI-2 can extend the interrupts and
utility signals not only to other mainframes, but also to any computers
and devices equipped with MXI-2.
In addition, MXI-2 surpasses the data throughput of previous-
generation MXIbus products by defining new high-performance
protocols. MXI-2 is a superset of MXI. All accesses initiated by
MXIbus devices will work with MXI-2 devices. However, MXI-2
defines synchronous MXI block data transfers that surpass previous
block data throughput benchmarks. The new synchronous MXI block
protocol increases MXI-2 throughput to a maximum of 33 MB/s
between two MXI-2 devices. All National Instruments MXI-2 boards
can initiate and respond to synchronous MXI block cycles.
Note:
In the remainder of this manual, the term MXIbus refers to MXI-2.
VME-MXI-2 Description
The VME-MXI-2 module is a double-height, single-width VMEbus
device with optional VMEbus System Controller functions. The
VME-MXI-2 can automatically determine if it is located in the first slot
of a VMEbus chassis and if it is the MXIbus System Controller.
The VME-MXI-2 module’s register set is based on VXI-6, VXIbus
Mainframe Extender Specification, Rev. 1.0. As a result, you can use
the VME-MXI-2 with a VXI-MXI-2 to connect VXI mainframes to
VMEbus mainframes.
The VME-MXI-2 converts A32, A24, A16, D64, D32, D16, and
D08(EO) VMEbus bus cycles into MXIbus bus cycles and vice versa.
The VME-MXI-2 has four address windows that map into and out of
the VMEbus mainframe. These four windows represent the three
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