Issue link: https://resources.mouser.com/i/1542831
C h a p t e r 1 | P C I e f o r I / O a n d P e r i p h e r a l C o n n e c t i v i t y Extended-distance connectivity also makes PCIe particularly valuable for distributed embedded systems. While copper is adequate for short runs within enclosures, many embedded designs now operate at long distances. For example, engineers may physically separate radios, sensors, and compute modules from host systems to gain more flexible thermal placement. In other cases, designers are adopting cabinet-to-cabinet architectures. In either case, systems can route PCIe over optical links to cover long distances and make root-complex-to- root-complex communication practical for redundant or partitioned systems through PCIe-based domain bridging. To support this model, multi-function PCIe switches combine switching, endpoint functionality, and industrial- grade interfaces into a single device. Integrated Ethernet, USB, RS-485, and GPIO endpoints reduce system complexity while keeping strict electrical and timing specifications intact. A design that previously required several separate interface chips can now use a single switch, resulting in better reliability and shorter bring-up time. In this topology, these devices act effectively as a "southbridge" for an embedded carrier board. Designers place a PCIe switch at the center of the carrier and build peripherals around it, treating the compute module as a replaceable component. Such a model improves product longevity because the peripheral map remains fixed even as compute modules change. Reliable, Consistent Evolution The true value of PCIe, however, is that it's both consistently reliable and growing. With each updated speficiation, PCI-SIG has added performance to a proven foundation without uprooting the status quo. Deepak Kumar Lnu Principal Engineer, R&D, Synopsys Inc. CPUs, accelerators, and storage all relied on different interfaces until PCIe unified everything into one fabric. Once PCIe is in place, the design becomes cleaner, easier to scale, and far simpler to maintain." 9 8 Experts Discuss PCIe for Emerging Embedded Systems