imrovements in spacewire test: international spacewire conference, nara, japan, 2008-11-6, paul...

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Imrovements in SpaceWire Test: International SpaceWire Conference, Nara, Japan, 2008-11-6, Paul Walker, Barry Cook, 4Links 1

Improvements in SpaceWire Test

Paul Walker, Barry Cook

4Links Limited

www.4Links.co.uk

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Content

Why record test results?

Why time-tag the recordings?

Resolving anomalies

Scalable recording

Monitoring Time Codes

Generating low-jitter Time Codes

RMAP Responder

Integrating all of these together

A real-life example for BepiColombo:

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Why record test results?

In Assembly, Integration and Validation (AIV/AIT) of satellites and their subsystems, you need to record the tests:

to resolve anomaliesto archive successful results as a reference

With a bus such as MIL 1553, a bus spy is fine

With SpaceWire, it is not so easy

4Links offer a solution

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Recording SpaceWire

Gbit Ethernet connection to PC with disc(s)

Any SpW Unit

Any SpW Unit

Any SpW Unit

Any SpW Unit

Any SpW Unit

Any SpW Unit

Multilink SpaceWire Recorder

Multi-link SpaceWire Recorder records up to four links

Records both directions of each link

Computer and disc(s) need to be fast and dedicated

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Why time-tag the records?

With 1553, traffic is purely sequential, but is time-tagged anyway.

SpaceWire has lots of concurent communications, so time tagging the records is even more important

With SpaceWire-RT, there is even more need to know when events occur in the network

Recordings are analyzed off-line to produce readable logs, for example:

10.079 194 952 0s 1<--2 Data @0000 05 55 30 1<--2 EOP at 10.079 195 552 0s (SOP + 0.600us) 10.079 195 792 0s 1<--2 Data @0000 05 55 30 1<--2 EOP at 10.079 196 392 0s (SOP + 0.600us)

Time-tag Direction Data

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Resolving anomalies

Pairs of packets should be arriving at 10ms intervals

Third packet arrives immediately after first pair, too early

Fourth packet arrives 20ms later, too late

10.480 772 121 4s 1<--2 Data @0000 05 55 32 1<--2 EOP at 10.479 772 721 4s (SOP + 0.600us) 10.480 772 961 4s 1<--2 Data @0000 05 55 37 1<--2 EOP at 10.479 773 561 4s (SOP + 0.600us) 10.480 773 800 0s 1<--2 Data @0000 05 55 70 1<--2 EOP at 10.479 774 401 4s (SOP + 0.601us) 10.680 351 792 0s 1<--2 Data @0000 05 55 73 1<--2 EOP at 10.680 352 392 0s (SOP + 0.600us)

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Scalable recording





Recorders need to be synchronized to preserve time relationship

Just connect the sync daisy chain and they synchronize

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Adding datation

IRIG Time of Year reference

Multi-link SpaceWire Recorder

Absolute Time Interface

The recorder is sychronized to an absolute reference clock, such as GPS, Loran, or the on-board clock

Synchronization is via the IRIG standard

IRIG references are available in rack units or boards

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Dated time-tagged records

Day:hh:mm:ss ms us ns Flow Activity288:15:25:10.263 728 870 1s 1<--2 Data @0000 01 02 03 04 05 06 07 08 1<--2 Data @0008 09 0A 0B 0C 0D 0E 0F 10 1<--2 Data @0010 11 12 13 14 15 16 17 18 1<--2 Data @0018 19 1A 1B 1C 1D 1E 1F 20 1<--2 Data @0020 21 22 23 24 25 26 27 28 1<--2 Data @0028 29 2A 2B 2C 2D 2E 2F 30 1<--2 Data @0030 31 32 1<--2 EOP at 288:15:25:10.263 731 370 1s (SOP+2.500us)288:15:25:15.249 072 811 5s 1<--2 Data @0000 01 02 03 04 05 06 07 08 1<--2 Data @0008 09 0A 0B 0C 0D 0E 0F 10 1<--2 Data @0010 11 12 13 14 15 16 17 18 1<--2 Data @0018 19 1A 1B 1C 1D 1E 1F 20 1<--2 Data @0020 21 22 23 24 25 26 27 28 1<--2 Data @0028 29 2A 2B 2C 2D 2E 2F 30 1<--2 Data @0030 31 32 1<--2 EOP at 288:15:25:15.249 075 311 5s (SOP+2.500us)

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Scalable datation







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Integrating Time Codes

The Absolute Time Interface has a SpaceWire port

Used to generate low jitter Time Codes

Default is 1pps Time Code

Optionally four Time Codes, as NASA/JWST, with settable intervals

All aligned to IRIG (hence to GPS or on-board clock)

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Datation on Time Codes

Time Codes are aligned to IRIG to within nanoseconds

Recordings can include mix of Time Codes and packets

Day:hh:mm:ss ms us ns Flow Activity288:15:19:31.000 000 000 5s 1-->2 Time Code 00288:15:19:32.000 000 000 5s 1-->2 Time Code 01288:15:19:33.000 000 000 5s 1-->2 Time Code 02288:15:19:34.000 000 000 5s 1-->2 Time Code 03288:15:19:35.000 000 000 5s 1-->2 Time Code 04288:15:19:36.000 000 000 5s 1-->2 Time Code 05288:15:19:37.000 000 000 5s 1-->2 Time Code 06288:15:19:38.000 000 000 5s 1-->2 Time Code 07288:15:19:38.869 933 928 8s 1<--2 Data @0000 01 02 03 04 05 06 07 08 1<--2 Data @0008 09 0A 0B 0C 0D 0E 0F 10 1<--2 Data @0010 11 12 13 14 15 16 17 18 1<--2 Data @0018 19 1A 1B 1C 1D 1E 1F 20 1<--2 Data @0020 21 22 23 24 25 26 27 28 1<--2 Data @0028 29 2A 2B 2C 2D 2E 2F 30 1<--2 Data @0030 31 32 1<--2 EOP at 288:15:19:38.869 936 428 8s (SOP+2.500us)288:15:19:39.000 000 000 5s 1-->2 Time Code 08288:15:19:40.000 000 000 5s 1-->2 Time Code 09

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12 hour Jitter accumulation

200ns/div

IRIG Reference edge

SpaceWire S signal, showing:

ESCDataStart of Null

Start of Time Code is aligned with IRIG

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8 hour Jitter accumulation

20ns/div

IRIG Reference edge

Leading edge of Time Code

Approx 30ns jitter in eight hours

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RMAP responder

RMAP needs support from test equipment

New RMAP resonder provides local memory for RMAP, managed by a computer

Provides ideal combination of low-latency responseconsistent access to the RMAP memoryfull control of RMAP memory by user

Existing product can be upgraded by replacing the plug-in memory card

Test functions appropriate for any stage of project

Diagnostic SpaceWire Interface DSI-RG408Diagnostic SpaceWire Interface DSI-RG408

Memory Card

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Integrating a test system



SpaceWire Packet Generator

Diagnostic SpaceWire Interface

RMAP Responder


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Diagnostic SpaceWire Interface DSI-RG408

Diagnostic SpaceWire Interface DSI-RG408

Test set for BepiColumbo

OBC

IRIG Reference

SpaceWire

Ethernet

Reference

Sync daisy-chain

RMAP Responer



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Recording SpaceWire packets is a necessary part of system verification

For detecting and resolving anomaliesFor archiving evidence clean runs

Records need to be time taggedTime tags often need to be dated

4Links provides the solutions, for any size of system, often with boxes you already have

Test functions appropriate for any stage of project

Diagnostic SpaceWire Interface DSI-RG408Diagnostic SpaceWire Interface DSI-RG408

Conclusions

imrovements in spacewire test: international spacewire conference, nara, japan, 2008-11-6, paul...

Documents

boardsdated time

time relationshipjust

dedicatedwhy time

time codestime codes

mix of time codes

pps time codeoptionally

low jitter time codesdefault

ns jitter