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Wikipedia

SpaceWire

April 09, 2024

SpaceWire is a spacecraft communication network based in part on the IEEE 1355 standard of communications. It is coordinated by the European Space Agency (ESA) in collaboration with international space agencies including NASA, JAXA, and RKA.

SpaceWire Specifications
Created byEuropean Space Agency
Speed2.0–400 Mbit/s
StyleSerial
Hotplugging interfaceYes
External interfaceYes
Websitespacewire.esa.int/WG/SpaceWire/
SpaceWire Connector Specifications
Type Data connector
Production history
Designer European Space Agency
General specifications
Hot pluggable Yes
External Yes
Audio signal No
Video signal No
Pins 9
Connector Micro-D
Data
Data signal Yes
Bitrate 2.0–400 Mbit/s
Protocol Serial
Pinout
Pin Name Description
Pin 1 DIN+ Data In Pos.
Pin 2 SIN+ Strobe In Pos.
Pin 3 Inner Shield Ground
Pin 4 SOUT- Strobe Out Neg.
Pin 5 DOUT- Data Out Neg.
Pin 6 DIN- Data In Neg.
Pin 7 SIN- Strobe In Neg.
Pin 8 SOUT+ Strobe Out Pos.
Pin 9 DOUT+ Data Out Pos.

Within a SpaceWire network the nodes are connected through low-cost, low-latency, full-duplex, point-to-point serial links, and packet switching wormhole routing routers.

Architecture edit

Physical layer edit

SpaceWire's modulation and data formats generally follow the data strobe encoding - differential ended signaling (DS-DE) part of the IEEE Std 1355-1995. SpaceWire utilizes asynchronous communication and allows speeds between 2 Mbit/s and 200 Mbit/s, with initial signalling rate of 10Mbit/s.[1] DS-DE is well-favored because it describes modulation, bit formats, routing, flow control, and error detection in hardware, with little need for software. SpaceWire also has very low error rates, deterministic system behavior, and relatively simple digital electronics. SpaceWire replaced old PECL differential drivers in the physical layer of IEEE 1355 DS-DE by low-voltage differential signaling (LVDS). SpaceWire also proposes the use of space-qualified 9-pin connectors.

SpaceWire and IEEE 1355 DS-DE allows for a wider set of speeds for data transmission, and some new features for automatic failover. The fail-over features let data find alternate routes, so a spacecraft can have multiple data buses, and be made fault-tolerant. SpaceWire also allows the propagation of time interrupts over SpaceWire links, eliminating the need for separate time discretes.

Link layer edit

Each transferred character starts with a parity bit and a data-control flag bit. If data-control flag is a 0-bit, an 8-bit LSB character follows. Otherwise one of the control codes, including end of packet (EOP).[2]

Network layer edit

The network data frames look as follows:

Address byte Address byte... Protocol ID Frame data

One or more address bytes are used for the routing. Addresses are either physical ones (0–31), or logical ones. The difference is that the physical addresses are deleted from the frame header during routing - which is used for hop-based routing (based on path specified in the frame itself). Logical addresses may be deleted as well, depending on the router configuration.

Interconnection edit

The hardware devices may be connected either directly, or via a SpaceWire router. In the former case, usually pairs of devices are used to guarantee a fail-safe operation, which is handled by the software.

A SpaceWire router is usually a crossbar switch-type device, operating in wormhole switching mode. This also may limit the speed of the communication to the lowest common speed.[3] The routing decisions are based on the programmed routing table and the initial incoming frame contents.

Uses edit

SpaceWire is used all around the globe.[4] Its use began primarily in ESA projects, but it is currently used by NASA, JAXA, RKA, and many other organizations and companies. Some NASA projects using it include the James Webb Space Telescope, Swift's Burst Alert Telescope, the Lunar Reconnaissance Orbiter, LCROSS, the Geostationary Operational Environmental Satellite (GOES-R), and the SCaN Testbed, previously known as the Communications, Navigation, and Networking Reconfigurable Testbed (CoNNeCT). It has also been selected by the United States Department of Defense for Operationally Responsive Space. SpaceWire initiatives are being coordinated between several space agencies in the frame of Consultative Committee for Space Data Systems (CCSDS) in order to extend its communication model to the network and transport layers of the OSI model.

SpaceWire supports highly fault-tolerant networks and systems, which is one reason for its popularity.[5]

Protocols edit

The ESA has a draft specification in place for the Protocol ID.

The following Protocol ID's have been assigned in ECSS-E-ST-50-11:

Protocol ID Name Description
1 Remote Memory Access Protocol (RMAP) used to remotely access/alter register configuration of the devices
2 CCSDS Packet Transfer Protocol [6] a common protocol used for sending Telecommands and receiving Telemetry
238 Proposal for Reliable Data Delivery Protocol (RDDP) used on GOES-R
239 Serial Transfer Universal Protocol (STUP) Used on SMCS-332 ASIC

References edit

  1. ^ "SpaceWire's User Guide" (PDF). Star-dundee.com. Retrieved 27 October 2019. chapter 3.3.5
  2. ^ "SpaceWire Characters". Star-dundee.com. Retrieved 28 October 2018.
  3. ^ "Radiation-Tolerant 10x SpaceWire Router" (PDF). Gaisler.com. Retrieved 28 October 2018.
  4. ^ "Who Uses SpaceWire? - STAR-Dundee". Star-dundee.com. Retrieved 28 October 2018.
  5. ^ Dr Barry M Cook; Paul Walker. "Ethernet over SpaceWire - software issues". 4links.co.uk, p. 2[dead link]
  6. ^ "Space Packet Transfer Protocol" (PDF). Public.ccsds.org. Retrieved 28 October 2018.

Other sources edit

  • ECSS-E-ST-50-12C - SpaceWire - Links, nodes, routers, and networks, ESA-ESTEC.
  • ECSS-E-50-12A (SUPERSEDED only document number has been changed to ECSS-E-ST-50-12C) SpaceWire - Nodes, links, and networks, ESA-ESTEC.
  • ECSS-E-ST-50-11C Draft 1.3 "Space engineering - SpaceWire protocols"

External links edit

  • SpaceWire Homepage (ESA)
  • European Cooperation for Space Standardisation - ECSS
  • 4Links Publications
  • International SpaceWire Conference 2010
  • International SpaceWire Conference 2011
  • International SpaceWire Conference 2013
  • STAR-Dundee Knowledge Database
  • http://www.interfacebus.com/SpaceWire_Avionics_Bus.html

SpaceWire IP Cores:

  • 4Links
  • STAR-Dundee
  • Aeroflex Gaisler
  • Astrium SpaceWire RMAP
  • CEA IRFU
  • CESR CNRS IRAP (CeCILL-C license)
  • OpenCores.org (SpaceWire and SpaceWire Light)
  • SpaceWire UK
  • European Space Agency
  • PnP Innovations

Articles:

  • NASA article on SpaceWire used on James Webb Space Telescope

April 09, 2024
spacewire, this, article, includes, list, general, references, lacks, sufficient, corresponding, inline, citations, please, help, improve, this, article, introducing, more, precise, citations, august, 2011, learn, when, remove, this, template, message, spacecr. This article includes a list of general references but it lacks sufficient corresponding inline citations Please help to improve this article by introducing more precise citations August 2011 Learn how and when to remove this template message SpaceWire is a spacecraft communication network based in part on the IEEE 1355 standard of communications It is coordinated by the European Space Agency ESA in collaboration with international space agencies including NASA JAXA and RKA SpaceWire SpecificationsCreated byEuropean Space AgencySpeed2 0 400 Mbit sStyleSerialHotplugging interfaceYesExternal interfaceYesWebsitespacewire wbr esa wbr int wbr WG wbr SpaceWire wbr SpaceWire Connector SpecificationsTypeData connectorProduction historyDesignerEuropean Space AgencyGeneral specificationsHot pluggableYesExternalYesAudio signalNoVideo signalNoPins9ConnectorMicro DDataData signalYesBitrate2 0 400 Mbit sProtocolSerialPinoutPinNameDescriptionPin 1DIN Data In Pos Pin 2SIN Strobe In Pos Pin 3Inner ShieldGroundPin 4SOUT Strobe Out Neg Pin 5DOUT Data Out Neg Pin 6DIN Data In Neg Pin 7SIN Strobe In Neg Pin 8SOUT Strobe Out Pos Pin 9DOUT Data Out Pos Within a SpaceWire network the nodes are connected through low cost low latency full duplex point to point serial links and packet switching wormhole routing routers Contents 1 Architecture 1 1 Physical layer 1 2 Link layer 1 3 Network layer 1 4 Interconnection 2 Uses 3 Protocols 4 References 5 Other sources 6 External linksArchitecture editPhysical layer edit SpaceWire s modulation and data formats generally follow the data strobe encoding differential ended signaling DS DE part of the IEEE Std 1355 1995 SpaceWire utilizes asynchronous communication and allows speeds between 2 Mbit s and 200 Mbit s with initial signalling rate of 10Mbit s 1 DS DE is well favored because it describes modulation bit formats routing flow control and error detection in hardware with little need for software SpaceWire also has very low error rates deterministic system behavior and relatively simple digital electronics SpaceWire replaced old PECL differential drivers in the physical layer of IEEE 1355 DS DE by low voltage differential signaling LVDS SpaceWire also proposes the use of space qualified 9 pin connectors SpaceWire and IEEE 1355 DS DE allows for a wider set of speeds for data transmission and some new features for automatic failover The fail over features let data find alternate routes so a spacecraft can have multiple data buses and be made fault tolerant SpaceWire also allows the propagation of time interrupts over SpaceWire links eliminating the need for separate time discretes Link layer edit Each transferred character starts with a parity bit and a data control flag bit If data control flag is a 0 bit an 8 bit LSB character follows Otherwise one of the control codes including end of packet EOP 2 Network layer edit The network data frames look as follows Address byte Address byte Protocol ID Frame dataOne or more address bytes are used for the routing Addresses are either physical ones 0 31 or logical ones The difference is that the physical addresses are deleted from the frame header during routing which is used for hop based routing based on path specified in the frame itself Logical addresses may be deleted as well depending on the router configuration Interconnection edit The hardware devices may be connected either directly or via a SpaceWire router In the former case usually pairs of devices are used to guarantee a fail safe operation which is handled by the software A SpaceWire router is usually a crossbar switch type device operating in wormhole switching mode This also may limit the speed of the communication to the lowest common speed 3 The routing decisions are based on the programmed routing table and the initial incoming frame contents Uses editSpaceWire is used all around the globe 4 Its use began primarily in ESA projects but it is currently used by NASA JAXA RKA and many other organizations and companies Some NASA projects using it include the James Webb Space Telescope Swift s Burst Alert Telescope the Lunar Reconnaissance Orbiter LCROSS the Geostationary Operational Environmental Satellite GOES R and the SCaN Testbed previously known as the Communications Navigation and Networking Reconfigurable Testbed CoNNeCT It has also been selected by the United States Department of Defense for Operationally Responsive Space SpaceWire initiatives are being coordinated between several space agencies in the frame of Consultative Committee for Space Data Systems CCSDS in order to extend its communication model to the network and transport layers of the OSI model SpaceWire supports highly fault tolerant networks and systems which is one reason for its popularity 5 Protocols editThe ESA has a draft specification in place for the Protocol ID The following Protocol ID s have been assigned in ECSS E ST 50 11 Protocol ID Name Description1 Remote Memory Access Protocol RMAP used to remotely access alter register configuration of the devices2 CCSDS Packet Transfer Protocol 6 a common protocol used for sending Telecommands and receiving Telemetry238 Proposal for Reliable Data Delivery Protocol RDDP used on GOES R239 Serial Transfer Universal Protocol STUP Used on SMCS 332 ASICReferences edit SpaceWire s User Guide PDF Star dundee com Retrieved 27 October 2019 chapter 3 3 5 SpaceWire Characters Star dundee com Retrieved 28 October 2018 Radiation Tolerant 10x SpaceWire Router PDF Gaisler com Retrieved 28 October 2018 Who Uses SpaceWire STAR Dundee Star dundee com Retrieved 28 October 2018 Dr Barry M Cook Paul Walker Ethernet over SpaceWire software issues 4links co uk p 2 dead link Space Packet Transfer Protocol PDF Public ccsds org Retrieved 28 October 2018 Other sources editECSS E ST 50 12C SpaceWire Links nodes routers and networks ESA ESTEC ECSS E 50 12A SUPERSEDED only document number has been changed to ECSS E ST 50 12C SpaceWire Nodes links and networks ESA ESTEC ECSS E ST 50 11C Draft 1 3 Space engineering SpaceWire protocols External links editThis section s use of external links may not follow Wikipedia s policies or guidelines Please improve this article by removing excessive or inappropriate external links and converting useful links where appropriate into footnote references July 2014 Learn how and when to remove this template message SpaceWire Homepage ESA European Cooperation for Space Standardisation ECSS 4Links Publications International SpaceWire Conference 2007 International SpaceWire Conference 2008 International SpaceWire Conference 2010 International SpaceWire Conference 2011 International SpaceWire Conference 2013 STAR Dundee Knowledge Database http www interfacebus com SpaceWire Avionics Bus htmlSpaceWire IP Cores 4Links STAR Dundee Aeroflex Gaisler Astrium SpaceWire RMAP CEA IRFU CESR CNRS IRAP CeCILL C license NASA Goddard tech transfer OpenCores org SpaceWire and SpaceWire Light SpaceWire UK European Space Agency PnP InnovationsArticles NASA article on SpaceWire used on James Webb Space Telescope Retrieved from https en wikipedia org w index php title SpaceWire amp oldid 1211844991, wikipedia, wiki, book, books, library,

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