National Instruments strives to provide quality products and ensure compatibility and flexibility for users. To achieve this goal, NI participates in industry-standard technology development groups and develops products that adhere to industry standards, where these standards exist, to ensure interoperability with other products. NI products interact effectively with components from other companies that are designed to industry standards. Examples include NI products based on GPIB, VXI, PCI, PCI Express, USB, PXI, and PXI Express.
NI MXI-Express RIO chassis implement a x1 PCI Express link to the host PC through a PCI Express board such as the NI PCIe-8362. The interfaces of PCI Express boards like the NI PCIe-8362 meet PCI Express standards. To ensure interoperability, these standards specify parameters such as voltage levels, signal encoding, bit rate, packet size, error detection mechanisms, and timing. A 100 MHz reference clock, provided by the host computer, is specified with detailed timing characteristics to serve as a timing reference for device communication. Peripheral cards and adapters—including graphics cards, network and storage adapters, communication devices, field-programmable gate arrays (FPGAs), and instrumentation cards that are designed to the specification—can communicate with the host PC if the host also complies with the specification.
Unfortunately, during interoperability testing on the NI MXI-Express RIO chassis, many PCs violated the specifications for the 100 MHz reference clock. This document describes the problem and recommends which PCs to use with an NI MXI-Express RIO expansion chassis.