3. summary
3
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Digital data buses
Development of DDB
ARING 429
MIL-STD-1553B
ARINC 629
Avionics, Lecture, Ivan, 2011
4. Data Bus, DB
4
Data bus is a subsystem that
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
transfers data between
computer components inside
a computer or between
computers.
Consists of
• Wire
• Information Packing equipment
• algorithms and formats of data
transition
Avionics, Lecture, Ivan, 2011
5. DB
5
•inside LRU;
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
•Between LRU;
•Transmit data from sensors to system;
•Between systems.
Avionics, Lecture, Ivan, 2011
6. www.OSTROUMOV.co.cc
OSTROUMOV IVAN
6
Do you recall
functional
integration?
Avionics, Lecture, Ivan, 2011
7. Distributed analog architecture
7
1950s, 1960s
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Lots of wire, no
bus
Very difficult to
modify
electro-
mechanical
parts
heavy, large
space, many
pieces
Boeing 707,
VC10, DC-9,
Boeing 737
Avionics, Lecture, Ivan, 2011
8. Distributed digital architecture
8
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Digital systems,
heavy, slow, difficult
to reprogram
(AN/ALQ-162)
Each component
contains its own
computer and
memory
Uses a bus between
components (less
wire)
Each unit has a
dedicated function
Difficult to expand
Boeing 737, 767
A330 (tanker),
Tornado, Sea Harrier
Avionics, Lecture, Ivan, 2011
9. www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Federated digital architecture
9
Systens communicate via a 1553B bus
Additions are easy, only requires that the
bus controller be reprogrammed
Can employ many buses to separate
common equipment (ex : EW on the F-18
with its own MC)
Avionics, Lecture, Ivan, 2011
10. www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Integrated modular architecture
10
Interchangeable modules can
realize diffrent system
functions
Permits on-board
repairs/swaps, that can
automatically reconfigure
Avionics, Lecture, Ivan, 2011
11. Common types of serial digital data transmission are:
11
Single source-single sink. This is the earliest application
and comprises a dedicated link from one piece of
equipment to another. This was developed in the 1970s
for use on Tornado and Sea Harrier avionics systems.
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Avionics, Lecture, Ivan, 2011
12. Common types of serial digital
12
data transmission are:
• Single source-multiple sink. This describes a
technique where one piece of transmitting
equipment can send data to a number of
recipient pieces of equipment (sinks). ARINC
429 is an example of this data bus which is
widely used by civil transport and business jets.
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Avionics, Lecture, Ivan, 2011
13. Common types of serial digital
13
data transmission are:
Multiple source-multiple sink. In this system, multiple
transmitting sources may transmit data to multiple
receivers. This is known as a full-duplex system and is
widely employed by military users (M1L-STD-1553B)
and by the B777 (ARINC 629).
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Avionics, Lecture, Ivan, 2011
14. The major digital data buses in
widespread use today in avionics
are:
14
ARINC 429 (A429).
MIL-STD-1553B, also covered by UK Def Stan 00-
18/Parts 1 and 2 and NATO STANAG 3838.
ARINC629 (A629).
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Avionics, Lecture, Ivan, 2011
15. www.OSTROUMOV.co.cc
SAE Standards
OSTROUMOV IVAN
15
AIR1189 Airborne Internal Interface Standards for Moderate Bit Rate Digital
Time Division - Multiplex Systems
AIR4013A Multiplex Data Bus Networks for Mil-Std-1760 Stores
ARP4258 Application of Low Speed Avionic System Discrete Signal Interfaces
AS15531 Digital Time Division Command/Response Multiplex Data Bus
AS4075 High Speed Ring Bus (Hsrb) Standard
AS4075/1 Optical Implementation Relating to the High Speed Ring Bus (Hsrb)
Standard
AS4710 Pi-Bus
AS5370 Multi-Transmitter Bidirectional Fiber-Optic Data Bus for Distributed
Aircraft Control Systems
AS5643 IEEE-1394b Interface Requirements for Military and Aerospace
Vehicle Applications
Avionics, Lecture, Ivan, 2011
16. www.OSTROUMOV.co.cc
OSTROUMOV IVAN
ARINC standards
16
ARINC 429. Digital Information Transfer System. Point-
to-point, 2-wire Bi-Polar Return-to-Zero signal. 32 bit
data. 100K or 12.5K bit rate.
ARINC 629. Multi-Transmitter Data Bus. Serial data bus
which operates over cable at 2Mbps. Developed by
Boeing.
ARINC 659. Backplane Data Bus for IMA, operates at
60Mbps as a commercial aviation bus.
ARINC 818. released in Jan. 07, is a video interface
and protocol standard developed for high bandwidth,
low latency, uncompressed digital video transmission.
Avionics, Lecture, Ivan, 2011
17. www.OSTROUMOV.co.cc
IEEE standarts
OSTROUMOV IVAN
17
IEEE-std-1393
Spaceborne Fiber Optic Data Bus (SFODB); 1 Gb/s, fiber.
Std 1149.5
Standard for Module Test and Maintenance Bus (MTM-Bus)
Protocol.
IEEE 1355
SpaceWire, based on the HIC (IEEE-1355) bus, and Low
Voltage Differential Signaling.
Avionics, Lecture, Ivan, 2011
18. www.OSTROUMOV.co.cc
Other buses include:
OSTROUMOV IVAN
18
Avionics Standard Communications Bus (ASCB), available in
several forms and based upon Ethernet protocols. ASCB was
developed by Honeywell and is used in General Aviation (GA)
and business jet applications.
Commercial Standard Data Bus (CSDB) developed by
Rockwell Collins for use in GA applications.
Avionics Full Duplex Ethernet (AFDX) based upon
commercial Fast Switched Ethernet (FDX) technology and
adopted for the Airbus A380.
In some applications, commercial RS 232 and RS 422 buses
are also used.
Avionics, Lecture, Ivan, 2011
21. www.OSTROUMOV.co.cc
Key attributes
OSTROUMOV IVAN
21
Simplex broadcast bus
Bit rates:
'High Speed' 100kbps
'Low Speed' 12 to 14.5kbps
Encoding: return to zero bipolar tri-state modulation
Message length: 32 bit word, 255 word data block in block transfer
mode
Media access: simplex single source multiple sink plus full duplex
Topology: single source multiple sink either star or bus
Number of nodes: 20 sinks, 1 source
Avionics, Lecture, Ivan, 2011
22. www.OSTROUMOV.co.cc
OSTROUMOV IVAN
22
The ARINC 429 specification defines the
requirements for a data transmission system based
on the use of a single data source and reception of
that data by up to 20 sinks or receivers. The
maximum number of receivers permitted for
connection to a source is limited by the specified
minimum receiver input impedance.
Avionics, Lecture, Ivan, 2011
26. www.OSTROUMOV.co.cc
Full duplex link
OSTROUMOV IVAN
26
Avionics, Lecture, Ivan, 2011
27. Return to Zero Bipolar Tri-state
27
Modulation
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Avionics, Lecture, Ivan, 2011
28. www.OSTROUMOV.co.cc
OSTROUMOV IVAN
28
The signal has three states 'HI', 'NULL' and 'LO'
represented by the differential voltage between the
two wires of the cable.
A logical ‘1’ is signalled by transmission of a +10
±1V pulse followed by a 0±0.5V null period.
A logical ‘0’ is signalled by transmission of a –10
±1V pulse also followed by a 0 ±0.5V null period.
Avionics, Lecture, Ivan, 2011
29. www.OSTROUMOV.co.cc
OSTROUMOV IVAN
29
Two ranges of transmission rate are defined.
'High Speed' at 100 kbps ±1% and
'Low Speed' in the range 12 to 14.5 kbps.
Avionics, Lecture, Ivan, 2011
30. www.OSTROUMOV.co.cc
Word format
OSTROUMOV IVAN
30
ARINC 429 organizes data in 32 bit words.
typical ARINC 429 word consisting of five parts:
• Label
• Source/Destination Identifier (SDI)
• Data field
• Sign/Status Matrix (SSM)
• Parity bit
Avionics, Lecture, Ivan, 2011
31. www.OSTROUMOV.co.cc
ARINC 429 Word Format
OSTROUMOV IVAN
31
Avionics, Lecture, Ivan, 2011
32. www.OSTROUMOV.co.cc
Label (data name)(1-8)
OSTROUMOV IVAN
32
each sink is required to inspect the Label field which
is encoded in octal to represent the type of
information contained within the 32-bit word.
Each data item is assigned a label code listed in the
ARINC 429 specification and each source may have
up to 255 Labels, assigned for its use.
Avionics, Lecture, Ivan, 2011
33. www.OSTROUMOV.co.cc
Source/ Destination Identifier (SDI)
OSTROUMOV IVAN
33
The SDI field contains just two bits.
The SDI’s functions are to:
indicate the intended destination of the data on
a multi-sink bus
identify the source of the data on a multi-source
bus (multi-system installation)
to add an extension to the Label, in which case
receiving systems decode the Label/SDI
combination.
Avionics, Lecture, Ivan, 2011
34. 34
www.OSTROUMOV.co.cc
OSTROUMOV IVAN
Avionics, Lecture, Ivan, 2011
35. www.OSTROUMOV.co.cc
Data formats
OSTROUMOV IVAN
35
two’s complement binary data
BCD (2/10) data
Discrete bits
Maintenance data
special Alphabet (Symbol and numeric)
Avionics, Lecture, Ivan, 2011
36. www.OSTROUMOV.co.cc
Sign/Status Matrix (SSM)
OSTROUMOV IVAN
36
It may be used to indicate sign information e.g. +, -,
compass direction etc. Each Label has its own unique
implementation of the SSM Sign function.
The SSM field may also be used to indicate the
source equipment status, operational mode or data
validity.
Avionics, Lecture, Ivan, 2011
37. www.OSTROUMOV.co.cc
Parity
OSTROUMOV IVAN
37
The parity bit is set to impose odd parity on the
word.
If even – mistake!!!!!
Avionics, Lecture, Ivan, 2011
39. www.OSTROUMOV.co.cc
Key attributes
OSTROUMOV IVAN
39
Serial time division command response data bus
Bit rate: 1Mbps
Encoding: baseband Manchester II bi-phase level
Message length: 1 to 32 16-bit words
Avionics, Lecture, Ivan, 2011
40. www.OSTROUMOV.co.cc
Структура MIL-STD-1553B
OSTROUMOV IVAN
40
Avionics, Lecture, Ivan, 2011
41. www.OSTROUMOV.co.cc
A typical example
OSTROUMOV IVAN
41
Note that a
module can be
both a bus
controller and a
remote terminal
Avionics, Lecture, Ivan, 2011
46. www.OSTROUMOV.co.cc
CW
OSTROUMOV IVAN
46
The standard defines three word formats
all words are 20 bit times long
The Command Word is issued only by a bus
controller and is used to convey commands to RTs.
Avionics, Lecture, Ivan, 2011
47. www.OSTROUMOV.co.cc
CW (Bit times)
OSTROUMOV IVAN
47
1 – 3 are used for an invalid Manchester
synchronising pattern.
4 – 8 contain the address of the RT that is to act on
the command (‘11111’ indicates a broadcast
command).
9 - the T/R bit, indicates to the receiving RT
whether it is to transmit (T/R = 1) or receive (T/R =
0) data words in response to the command.
Avionics, Lecture, Ivan, 2011
48. www.OSTROUMOV.co.cc
CW (Bit times)
OSTROUMOV IVAN
48
10 – 14, if set to ‘00000’ or ‘11111’, indicate that the
next 5 bits are to be interpreted as a mode code. If set
to any other value they indicate a subaddress within the
subsystem served by the RT that is to source or receive
data.
15 – 16 indicate either a mode code that requires the
RT to perform some control function (e.g. Reset, Initiate
Self Test etc.) or the number of Data Words to be either
received or transmitted by the RT.
Bit 20 is a parity bit set for odd parity over the
previous 16 bits.
Avionics, Lecture, Ivan, 2011
49. www.OSTROUMOV.co.cc
Data Words
OSTROUMOV IVAN
49
Data Words may be transmitted either by the BC or
RT.
Bits 1 – 3 are used for an invalid Manchester
synchronising pattern.
Bits 4 – 19 contain the data to be conveyed. Bit 20
is the parity bit.
Avionics, Lecture, Ivan, 2011
50. www.OSTROUMOV.co.cc
Status Words
OSTROUMOV IVAN
50
Status Words are transmitted only by RTs and are
used to indicate to the BC the state of the RT and
the RT’s view of recent events on the bus. For
example, certain status bits are used to indicate
whether there is a fault in the subsystem or terminal
and others the results of error checking, broadcast
message reception and service request (latent
interrupt) conditions.
Avionics, Lecture, Ivan, 2011
51. www.OSTROUMOV.co.cc
Status Words
OSTROUMOV IVAN
51
Bit times 1 – 3 are used for an invalid Manchester
synchronising pattern.
Bits 4 – 8 contain the address of the RT transmitting
the Status word.
Bits 9 – 11 and 15 – 19 are the status bits and bits
12 – 14 are reserved and unused (always ‘0’).
Avionics, Lecture, Ivan, 2011
52. www.OSTROUMOV.co.cc
Data Transfer Message Formats
OSTROUMOV IVAN
52
Avionics, Lecture, Ivan, 2011
53. www.OSTROUMOV.co.cc
Принцип передачі даних MIL-STD-1553B
OSTROUMOV IVAN
53
Avionics, Lecture, Ivan, 2011
57. www.OSTROUMOV.co.cc
Key attributes
OSTROUMOV IVAN
57
ARINC specification 629 Multi-transmitter Data Bus
Serial data bus with distributed media access.
Bit rate: 2Mbps.
Encoding: Manchester II bi-phase.
Message length: up to 31 Word Strings each
containing one 16 bit label word and up to two
hundred and fifty-six 16 bit data words
Number of nodes: up to 120.
Avionics, Lecture, Ivan, 2011
