Chapter 3 hardware overview, Functional overview, Functional overview -1 – National Instruments 8330 Series User Manual

Page 17: Hardware overview

background image

© National Instruments Corporation


PXI-PCI 8330 Series User Manual


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 initiates configuration
cycles and searches for PCI devices on the secondary side.

Figure 3-1 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 Gbits/s. If you are using copper cable, the system sends the serial data
through the cable as a differential electrical signal. If you are using
fiber-optic cable, the system converts the serial data to light using a
VCSEL module.

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 in the
case where a fiber-optic MXI-3 is used. 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.