Hot-plug based activation and deactivation of ATCA FRU devices

One of the most important features of the Advanced Telecommunications Computing Architecture (ATCA) contributing to its exceptional reliability and availability is its hot-swap functionality. In order for the user to be able to add and remove the components of an ATCA shelf without the necessity of switching the power on and off the PCI Industrial Computer Manufacturers Group (PICMG) specification clearly enumerates the stages a Field Replaceable Unit (FRU) has to go through upon insertion into and extraction from the shelf. These stages form the activation and deactivation processes that occur every time an element is changed in the ATCA system. This paper focuses on these processes placing the emphasis on the Electronic Keying (EK) implementation in the Intelligent Platform Management Controller (IPMC) software developed for the self-designed ATCA Carrier Board (CB). This CB is considered to be used in the Low Level RF (LLRF) control system of the X-Ray Free Electron Laser (XFEL). It utilizes the standard-defined PCI Express (PCIe) interface as well as introduces proprietary protocols in form of Low Latency Links (LLL)