© National Instruments Corporation 3-1 PXI-PCI 8330 Series User Manual
3
Hardware Overview
This chapter presents an overview of the hardware functions of your MXI-3
system, and explains the operation of each functional unit.

Functional Overview

The MXI-3 system is a PCI-PCI bridge that needs no software for normal
operation. When the desktop PC or the CompactPCI/PXI controller
powers on, the system BIOS scans its local PCI bus for devices. When it
finds the primary interface of the MXI-3 card, it opens memory windows
in the card and searches for PCI devices through those windows using PCI
transactions. The PC recognizes alldevices on the secondary bus to be on
a single PCIbus.
Figure 3-1, MXI-3 Block Diagram, shows the basic architecture of the
MXI-3 system. The MXI-3 card interfaces to the PCI bus with the National
Instruments MXI-3 ASIC. The ASIC converts PCI transactions into a
20-bit wide parallel bus. A parallel to serial converter transmits the 20-bit
data as serial data at 1.5 GBytes/s. If you are using copper cable, the system
sends the unmodified serial data through the cable. If you are using
fiber-optic cable, the system converts the serial data to light using a
VCSELm odule.
On the other side of the system, the MXI-3 card receives the data, using
high-speed photodetectors to convert light signals back to digital data if
necessary. A serial to parallel converter then converts the digital serial data
to the original 20-bit wide packets of data for the MXI-3 ASIC. MXI-3 then
recreates the PCI transaction with appropriate modifications.