"A Radiation Hardened SpaceWire ASIC and Roadmap"
Richard Berger1, Myrna Milliser1, Paul Kapcio1, Dan Stanley1, David Moser1, Jennifer Koehler1, Glenn Rakow2, and Richard Schnurr2
2NASA Goddard Space Flight Center
An Application Specific Integrated Circuit (ASIC) that implements the SpaceWire protocol has been developed in a radiation hardened 0.25 micron CMOS technology. This effort began in March 2003 as a joint development between the NASA Goddard Space Flight Center (GSFC) and BAE Systems. The BAE Systems SpaceWire ASIC is comprised entirely of reusable core elements, many of which are already flight-proven. It incorporates a 4-port SpaceWire router with two local ports, dual PCI bus interfaces, a microcontroller, 32KB of internal memory, and a memory controller for additional external memory use. The SpaceWire ASIC is planned for use on both the Geostationary Operational Environmental Satellites (GOES)-R and the Lunar Reconnaissance Orbiter (LRO). Engineering parts have already been delivered to both programs.
This paper discusses the SpaceWire protocol and those elements of it that have been built into the current SpaceWire reusable core. There are features within the core that go beyond the current standard that can be enabled or disabled by the user and these will be described. The adaptation of SpaceWire to BAE Systems' On Chip Bus (OCB) for compatibility with the other reusable cores will be discussed. Optional configurations within user systems will be shown. The physical implementation of the design will be described and test results from the hardware will be discussed. Finally, the BAE Systems roadmap for SpaceWire developments will be discussed, including some products already in design as well as longer term plans.
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