Space Wire Remote Memory Access Protocol

Abstract

SpaceWire is a spacecraft onboard communications network used to connect together electronic sub-systems like sensors, mass-memory, processors, control and telemetry/telecommand units. SpaceWire provides high bandwidth communication using point-to-point links between sub-systems or networked interconnection using routing switches to forward packets of data across the network. SpaceWire has a simple interface which can be readily implemented in a range of different chip technologies including Field Programmable Gate Arrays (FPGAs). The SpaceWire standard defines “links, nodes and routers. ” It does not define any higher level communications standards for operating over the SpaceWire network other than straightforward packet encapsulation. This paper describes the Remote Memory Access Protocol for SpaceWire which provides a standard method of reading and writing to registers and memory within a SpaceWire unit by sending a command and where appropriate receiving a reply across the network. 1.