MXI-Express x16 is based on PCI Express technology.
A MXI-Express x16 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. The PCI Express switch architecture is transparent to device drivers, so no additional software is needed to support using PXI Express and CompactPCI Express devices in a chassis connected using MXI-Express x16.
The PXI Platform Services software on the PXI Platform Services CD or driver CD included with your PXI Express MXI-Express x16 hardware is required to provide chassis and controller identification for PXI features such as trigger routing and slot detection. The PXI Platform Services software also is included with the NI-DAQmx and NI-VISA drivers. For more information, refer to KnowledgeBase 3TJDOND8 at ni.com.
The link between the PC and the chassis is a x16 PCI Express link. This link is a dual-simplex communication channel comprised of low-voltage, differentially driven signal pairs. The link can transmit at a rate of 8 Gbytes/s in each direction simultaneously, though protocol overhead and other inefficiencies reduce the achievable throughput.
The following figure shows the basic architecture of MXI-Express x16. The PCIe-8388 consists of a PCI Express x16 board edge connector, PCI Express repeaters, and one cabled MXI-Express x16 connector. The PXIe-8388/9 consists of one or two cabled MXI-Express x16 connectors, a PCI Express switch, and PXI Express connectors.
A MXI-Express x16 system consists of the following functional units:
On the PXIe-8388/9, the switch upstream port is connected to the cable PORT 1. One downstream port is connected to the SMBus Master, one x16 port is connected to PORT 2 (PXIe-8389 only), and four x4 ports or one x8 and one x16 port are connected to the backplane, depending on the chassis backplane configuration.