Remoting field bus control by means of a PCI Express-based optical serial link

A major evolution moved into the I/O architecture of modern computers, where the multi-drop buses have been replaced by a network of point-to-point links. Besides the increased throughput and the inherent parallelization of the data flows, the serial nature of those links and the packet-based protocols allow an easy geographical decoupling of a peripheral device. In the context of the LINCO project, we investigated the possibility of using an optical physical layer for the PCI Express, and we built a bus adapter which can bridge, through such a link, remote buses (>100 m) to a single-host computer without even the need of a specialized driver, given the legacy PCI compatibility of the PCI Express hardware. By the choice of suitable components and dedicated control logic, the adapter has been made tolerant to harsh environmental conditions, like strong magnetic fields or radiation fluxes, that the data acquisition needs of high-energy physics experiments often require.