Bsi bs en 16603 50 51 2014

BS EN 16603-50-51:2014

BSI Standards Publication

Space engineering —
SpaceWire protocol
identification


BS EN 16603-50-51:2014

BRITISH STANDARD

National foreword
This British Standard is the UK implementation of EN
16603-50-51:2014.
The UK participation in its preparation was entrusted to Technical
Committee ACE/68, Space systems and operations.
A list of organizations represented on this committee can be
obtained on request to its secretary.
This publication does not purport to include all the necessary
provisions of a contract. Users are responsible for its correct
application.
© The British Standards Institution 2014. Published by BSI Standards
Limited 2014
ISBN 978 0 580 84192 7
ICS 49.140
Compliance with a British Standard cannot confer immunity from
legal obligations.
This British Standard was published under the authority of the
Standards Policy and Strategy Committee on 30 September 2014.

Amendments issued since publication
Date

Text affected


BS EN 16603-50-51:2014

EN 16603-50-51

EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM

September 2014

ICS 49.140

English version

Space engineering - SpaceWire protocol identification
Ingénierie spatiale - SpaceWire identifieur de protocole

Raumfahrttechnik - SpaceWire Protokoll zur Identifikation

This European Standard was approved by CEN on 1 March 2014.
CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving
this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning
such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN and CENELEC
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN and CENELEC member into its own language and notified to the CEN-CENELEC Management Centre
has the same status as the official versions.
CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
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Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

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© 2014 CEN/CENELEC All rights of exploitation in any form and by any means reserved
worldwide for CEN national Members and for CENELEC
Members.

Ref. No. EN 16603-50-51:2014 E


BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)

Table of contents
Foreword .................................................................................................................... 3
1 Scope ....................................................................................................................... 4
2 Normative references ............................................................................................. 5
3 Terms, definitions and abbreviated terms............................................................ 6
3.1

Terms defined in other standards .............................................................................6

3.2

Terms specific to the present standard .....................................................................6

3.3

Abbreviated terms.....................................................................................................8

3.4

Conventions..............................................................................................................8

4 Principles ................................................................................................................ 9
5 Requirements........................................................................................................ 10
5.1

Overview ................................................................................................................10

5.2

Protocol identification..............................................................................................10
5.2.1

Addressing ................................................................................................10

5.2.2

Protocol Identifier ......................................................................................11

5.2.3

Extended Protocol Identifier ...................................................................... 11

5.2.4

Ignoring unknown protocols ...................................................................... 12

5.2.5

Protocol Identifier and Extended Protocol Identifier Allocation ................... 12

Bibliography............................................................................................................. 14
Figures
Figure 5-1: Protocol Identifier position ..................................................................................11
Figure 5-2: Extended Protocol Identifier ...............................................................................12

Tables
Table 5-1: Protocol identifier allocation .................................................................................13

2


BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)

Foreword
This document (EN 16603-50-51:2014) has been prepared by Technical
Committee CEN/CLC/TC 5 “Space”, the secretariat of which is held by DIN.
This standard (EN 16603-50-51:2014) originates from ECSS-E-ST-50-51C.
This European Standard shall be given the status of a national standard, either

by publication of an identical text or by endorsement, at the latest by March
2015, and conflicting national standards shall be withdrawn at the latest by
March 2015.
Attention is drawn to the possibility that some of the elements of this document
may be the subject of patent rights. CEN [and/or CENELEC] shall not be held
responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CEN by the
European Commission and the European Free Trade Association.
This document has been developed to cover specifically space systems and has
therefore precedence over any EN covering the same scope but with a wider
domain of applicability (e.g. : aerospace).
According to the CEN-CENELEC Internal Regulations, the national standards
organizations of the following countries are bound to implement this European
Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.

3


BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)

1
Scope
There is a number of communication protocols that can be used in conjunction
with the SpaceWire Standard (ECSS-E-ST-50-12), to provide a comprehensive

set of services for onboard user applications. These protocols are covered by the
ECSS-E-ST-50-5x series.
To distinguish between the various protocols a protocol identifier is used. This
Standard specifies this protocol identifier.
This standard may be tailored for the specific characteristic and constrains of a
space project in conformance with ECSS-S-ST-00.

4


BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)

2
Normative references
The following normative documents contain provisions which, through
reference in this text, constitute provisions of this ECSS Standard. For dated
references, subsequent amendments to, or revision of any of these publications
do not apply. However, parties to agreements based on this ECSS Standard are
encouraged to investigate the possibility of applying the more recent editions of
the normative documents indicated below. For undated references, the latest
edition of the publication referred to applies.

EN reference

Reference in text

Title

EN 16601-00-01

ECSS-S-ST-00-01

ECSS system - Glossary of terms

EN 16603-50-12

ECSS-E-ST-50-12

Space engineering - SpaceWire - Links, nodes, routers
and networks

EN 16603-50-52

ECSS-E-ST-50-52

Space engineering - SpaceWire - Remote memory
access protocol

EN 16603-50-53

ECSS-E-ST-50-53

Space engineering - SpaceWire - CCSDS packet
transfer protocol

CCSDS 133.0-B-1

Space Packet Protocol, Blue Book

SMCS-ASTD-PS-001
Issue 1.1, 24 July 2009

STUP SpaceWire Protocol - Protocol Specification,
EADS Astrium ASE4

417-R-RTP-0050
Version 2.1, 16 January
2008

Geostationary Operational Environmental Satellites
(GOES), GOES-R Series, GOES-R Reliable Data
Delivery Protocol (GRDDP), NASA Goddard
Spaceflight Centre

5


BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)

3
Terms, definitions and abbreviated terms
3.1

Terms defined in other standards
For the purpose of this Standard, the terms and definitions from ECSS-S-ST-00-01
apply.

3.2

Terms specific to the present standard
3.2.1

byte

8-bits where bit 7 is the most-significant bit

3.2.2

command

instruction to a SpaceWire node (target) to perform some action
NOTE

3.2.3

For example, write data to memory.

command packet

packet that contains a command

3.2.4

confirmation

primitive passed from a service provider to a service user to indicate the success
or otherwise of a previous service request

3.2.5

data character

SpaceWire symbol containing 8-bits of user information

3.2.6

Error End of Packet marker (EEP)

control character indicating that the Packet was terminated prematurely

3.2.7

End of Packet marker (EOP)

control character indicating the end of a packet

3.2.8

extender protocol identifier

two data characters following a protocol identifier which has value 0x00 that
identify a particular protocol being used for communication

6


BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)

3.2.9

indication

primitive passed from a service provider to a service user to provide
information or status to the service user

3.2.10

initiator

SpaceWire node that starts a transaction by sending a command to a SpaceWire
node

3.2.11

initiator user application

application in an initiator that is using the SpaceWire protocol services

3.2.12

logical address

identifier of a initiator or target which can be used to route a Packet to the target
or, if path addressing is being used, to confirm that the final target is the correct
one i.e. that the logical address of the target matches the logical address in the
packet

3.2.13

memory

addressable storage element including random access memory, registers, FIFO,
mailboxes

3.2.14

packet

SpaceWire packet

3.2.15

path address

sequence of one or more SpaceWire data characters that defines the route to a
target by specifying, for each router encountered on the way to the target, the
output port that a Packet is forwarded through

3.2.16

protocol identifier

data character
communication

3.2.17

that

identifies

a

particular

protocol

being

used

for

reply

response sent by a target to the initiator or some other node expecting the reply
to provide the required information or to indicate that some commanded action
has been completed by the target

3.2.18

reply packet

packet containing a reply

3.2.19

request

primitive passed from a service user to a service provider to request a service

3.2.20

response

primitive passed from a service user to a service provider in response to an
indication from the service provider

7


BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)

3.2.21

target

SpaceWire node that responds to a command sent by an initiator

3.2.22

target user application

application in a target that is using the SpaceWire protocol services

3.2.23

transaction

interaction between an initiator and a target

3.2.24

word

multiple bytes held in a single memory location

3.3

Abbreviated terms
The following abbreviations are defined and used within this standard:

3.4

Abbreviation

Meaning

CCSDS

Consultative Committee for Space Data Systems

EEP

error end of packet

EOP

end of packet

FIFO

first in first out

ID

identifier

RMAP

remote memory access protocol

VHSIC

very high speed integrated circuit

Conventions
In this document hexadecimal numbers are written with the prefix 0x, for
example 0x34 and 0xDF15.
Binary numbers are written with the prefix 0b, for example 0b01001100 and
0b01.
Decimal numbers have no prefix.

8

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EN 16603-50-51:2014 (E)

4
Principles
To distinguish between the various protocols that can be used in conjunction
with the SpaceWire protocol defined in ECSS-E-ST-50-12, a protocol identifier is
used. This standard specifies such a protocol identifier. The protocols that
operate over SpaceWire are then specified in the ECSS-E-ST-50-5x series of
standards.
Examples of these protocols are:
•

Remote Memory Access Protocol (RMAP)
The aim of RMAP is to support reading from and writing to memory in a
remote SpaceWire node. RMAP can be used to configure a SpaceWire
network, control SpaceWire nodes, and to transfer data to and from
SpaceWire nodes. RMAP is specified in ECSS-E-ST-50-52.

•

CCSDS Packet Transfer Protocol
The aim of the CCSDS Packet Transfer Protocol is to transfer CCSDS
Packets across a SpaceWire network. It does this by encapsulating the
CCSDS Packet in a SpaceWire packet, transferring it across the
SpaceWire network and then extracting the CCSDS Packet at the target.
The CCSDS Packet Transfer Protocol is specified in ECSS-E-ST-50-53.

9

BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)

5
Requirements
5.1

Overview
The protocol identification scheme enables many different protocols to operate
concurrently over a SpaceWire network without them interfering with each
other. To achieve this, an identifier is given to each protocol. Nodes receiving
packets process and respond to them according to the protocol specified by the
Protocol Identifier in the packet. If a packet arrives with a particular Protocol
Identifier that is not supported by a node then it is ignored.

5.2

Protocol identification
5.2.1
a.

b.

Addressing

A packet containing a Protocol Identifier shall start with a single byte
logical address when it arrives at the target.
NOTE 1

See Figure 5-1.

NOTE 2

When sent by the initiator the packet can have
one or more leading path or logical address
bytes which are stripped off (SpaceWire
Address) on the way through the SpaceWire
network leaving the single logical address byte
when it arrives at the target.

The logical address 254 (0xFE) shall be used as a default value when the
target does not have another value specified for its logical address.
NOTE

c.

A target may choose to ignore packets with logical address 254 (0xFE).
NOTE

d.

If a packet with a logical address is ignored
then the target can record and make available a
count of the number of packets it received and
ignored with logical address 254 (0xFE).

A target may accept packets with one or more different logical address
values.
NOTE

10

When the initiator does not know the logical
address of the target the default logical address
254 (0xFE) can be used.

For example, a node accepting packets with
logical addresses 60, 61 or 254.


BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)

5.2.2
a.

Protocol Identifier

A Protocol Identifier shall comprise a single byte immediately following
the logical address.
NOTE

b.

A value of zero shall be used to identify an Extended Protocol Identifier.
NOTE

c.

See Figure 5-1.
The value of zero in the Protocol Identifier byte
is reserved for extension of the Protocol
Identifier, as specified in clause 5.2.3.

A Protocol Identifier with a value of 255 (0xFF) shall not be used.
NOTE
Logical
Address

It is reserved for future use.
Protocol
ID

Logical Address with Protocol ID
SpW
Address

Logical
Address

Protocol
ID

SpaceWire Address and Logical Address with Protocol ID

Figure 5-1: Protocol Identifier position

5.2.3
a.

b.

Extended Protocol Identifier

If an Extended Protocol Identifier is supported, the following shall apply:
1.

Protocol Identifier has the value zero (0x00).

2.

The two bytes following the reserved Protocol Identifier (zero)
form a 16-bit Extended Protocol Identifier.
NOTE 1

This allows up to 65535 protocols to be carried
over a SpaceWire network.

NOTE 2

An Extended Protocol Identifier need not be
implemented.

NOTE 3

See Figure 5-2.

If an Extended Protocol Identifier is not supported, then a packet with a
Protocol Identifier with the value zero (reserved Protocol Identifier) shall

be discarded when received.
NOTE

If a target ignores the Extended Protocol
Identifier then it can record and make available
a count of the number of packets it received
with an Extended Protocol Identifier.

c.

Extended Protocol Identifiers with values in the range 0x0000 to 0x00FF
are reserved and shall not be used.

d.

A packet with an Extended Protocol Identifier with a value in the range
0x0000 to 0x00FF shall be discarded when received.
NOTE

These values are reserved for future use.

11


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EN 16603-50-51:2014 (E)

Logical
Address

Extended
Extended
Protocol ID
Protocol ID Protocol ID
(0x00)
MS
LS

Logical Address with Extended Protocol ID

SpW
Address

Logical
Address

Extended Extended
Protocol ID
Protocol ID Protocol ID
(0x00)
MS
LS

SpaceWire Address and Logical Address with Extended Protocol ID

Figure 5-2: Extended Protocol Identifier

5.2.4
a.

Ignoring unknown protocols

If a packet arrives with a Protocol Identifier or Extended Protocol
Identifier that is not supported (unknown) by that target then the packet
shall be discarded.
NOTE

5.2.5
a.

b.

Protocol Identifier and Extended Protocol
Identifier Allocation

Protocol Identifiers in the range 1 to 239 (0x01 to 0xEF) that shall be used
are those listed in Table 5-1.
NOTE 1

The identifiers in Table 5-1 have been assigned
by the SpaceWire working group. The protocols
starting at number 1 and working upwards as
defined in this standard document define the
current set of approved SpaceWire protocols
and their Protocol Identifiers. The protocols
starting at 239 and working downwards are
legacy protocols and are not covered by this
standard document.

NOTE 2

The reader is advised to consult the SpaceWire
website () for the
latest Table defining the Protocol Identifiers
and Extended Protocol Identifier allocation.

Protocol Identifiers in the range 240 to 254 (0xF0 to 0xFE) shall be
assigned by the project.
NOTE 1

12

The target can count the number of packets that
arrive at a target with unknown Protocol
Identifier or Extended Protocol Identifier can be
kept and made available by the target.

Developers can use these Protocol Identifiers
but it is important to note that they can clash
with protocols being developed by other users.
Concurrent operation of different protocols is


BS EN 16603-50-51:2014
EN 16603-50-51:2014 (E)
only assured for Protocol Identifiers in the
range 1 to 239 (0x01 to 0xEF).
NOTE 2

Proven protocols can be recommended for

adoption by the SpaceWire working group and
then be included in future revisions or
extensions to this SpaceWire Protocols
standard. Once adopted they are given a
unique Protocol Identifier in the range 1 to 239.

NOTE 3

No Extended Protocol Identifiers have been
allocated.

Table 5-1: Protocol identifier allocation
Protocol Identifier

Protocol

Specified in

0

Extended Protocol Identifier

Clause 5

1

Remote Memory Access Protocol

ECSS-E-ST-50-52

2

CCSDS Packet Transfer Protocol

ECSS-E-ST-50-53

238

GOES-R Reliable Data Delivery
Protocol

417-R-RTP-0050 Version 2.1,
16 January 2008

239

Serial Transfer Universal Protocol

SMCS-ASTD-PS-001 Issue 1.1,
24 July 2009

13


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EN 16603-50-51:2014 (E)

Bibliography
EN reference

Reference in text

Title

EN 16601-00

ECSS-ST-S-00

ECSS system - Description, implementation
and general requirements



SpaceWire website

14


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