Functional Overview
- Updated2023-02-18
- 4 minute(s) read
Functional Overview
MXI-Express x4 is based on PCI Express technology. A MXI-Express x4 kit uses PCI Express switches to enable control of a PXI Express or CompactPCI Express chassis from a PC with an available PCI Express slot, or from a PXI Express chassis with an available PXI Express slot. The switch architecture is transparent to device drivers, so no additional software is needed for CompactPCI Express level support for PXI Express devices in connected chassis.
The link between the PC and the chassis is a x4 cabled PCI Express link. This link is a dual-simplex communication channel comprised of four low-voltage, differentially driven signal pairs. The link can transmit at a rate of 10 Gbps in each direction simultaneously.
The BIOS of some host machines may not support the extension of the PCI-Express fabric or PCI bus. Because this is the primary function of MXI-Express x4 products, those systems may not boot or function correctly. To address this issue, certain MXI-Express x4 products have additional functionality intended to hide all PCI or PCI-Express resources that are connected to the host machine, and allow NI MXI-Express BIOS Compatibility Software to handle the enumeration process of these resources instead of the BIOS.
In the cases where this software is required, there may be a dip switch on the board that needs to be toggled as instructed by the documentation for the software. The functional block diagram illustrates the location and availability of the dip switch package. Only the first dip switch in the package is used for this purpose. The other switches serve no function and should be left in their default position.[1]
PCIe-8371 Overview
With the PCIe-8371, you can control PXI Express and CompactPCI Express systems from a x4 or higher PCI Express slot in your desktop or server PC.
The PCIe-8371 includes one x4 PCI Express link that provides up to 798 MB/s of sustained throughput when cabled to a single PXI Express chassis. The PXIe-PCIe-8371 kit consists of an PCIe-8371 in the PC connected via a x4 MXI-Express cable to a PXI Express module in slot 1 of a PXI Express chassis.
PCIe-8371 Block Diagram
Basic MXI-Express x4 System
The simplest MXI-Express x4 system consists of a PCIe-8371/8372 in a PC connected to a PXIe-8370 in the controller slot of a PXI Express chassis, as shown in the following figure.
Larger MXI-Express x4 Systems
The PCIe-8372 has two MXI-Express x4 connectors, allowing one PCIe-8372 to host two different PXIe-8370 cards in separate PXI Express or CompactPCI Express chassis. If multiple PCI Express slots are available in the host PC, you can connect additional PXI Express chassis by installing an additional PCIe-8371/8372 in any available PCI Express slot.
You can also daisy-chain from a PXI Express chassis already controlled by an embedded controller, host PC, or laptop to additional PXI Express chassis using MXI-Express x4 products.
The following figures show how you can use MXI-Express x4 cards to connect multiple PXI Express expansion chassis to a PC in a star or daisy-chain topology.
1 On certain legacy MXI-Express x4 products that contain the dip switch package, the secondary switches may serve a reserved purpose.