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<sup>[[{{TALKPAGENAME}}#With Respect to What|[With Respect to What?] ]]</sup> {{-}} {{Citation needed|date=July 2009}} {{-}} {{compu-hardware-stub}} {{-}} {{disambig}}


This page is about the commercial product named Time Triggered Protocol or TTP (registered trademark of TTTech), which embodies an implementation of a time-triggered communication protocol; for other implementations , see Time-Triggered Communication Protocol

Time-Triggered Protocol (Disambiguation)

this article oa about the general TDMA method, for the commercial product, see TTP

Time-Triggered Protocol (Disambiguation)

A time-triggered communication protocol is a method of communication wherein a sequence of scheduled communication actions, distributed amungst multiple transmitters sharing a common channel, is repeated in a periodic cycle. [shorten]

  • TTP is a registered trademark of TTTech

Time-Triggered Communication Protocol, Time-Triggered Protocol, or Time Triggered Protocol, or refer to a class of communication protocols that employ cyclic, isochronous scheduling of bus access by multiple transmitters, generally in the form of time division multiple access (TDMA).[1]

Time-triggered communication protocols generally provision for a fixed and repeating schedule of isochronous transmissions where channel access is distributed among multiple transmitters. The schedule (or cycle) may be divided into a fixed schedule of sub-cycles, each having a different but fixed schedule of transmissions. Portions of such cycles may be given over to other forms of non-isochronous channel access controls; for example, a cyclic time window or slot may be given over for a fixed period of asynchronous bus access, such as a limited period of CDMA arbitration as in the case of TTCAN.

SAE AS6803, TTP Communication Protocol

Distinctions from other classes of communication protocols[edit]


Protocol Access Schedule
time-triggered multiple cyclic distributed a priori
MIL-STD-1553 multiple cyclic central a priori
ARINC 429 single cyclic distributed a priori
USB multiple cyclic distributed ad hoc

distributed vs. central schedule[edit]

Time-triggered protocols rely on a distributed channel access schedule; that is, each transmitter node must have (1) a means of synchronization with the network schedule and (2) knowledge of when it is scheduled to have channel access within that schedule. More simply put, every node must be able to schedule itself such that it transmits it signals only within in its allotted time slots. Thus, these protocols are distinct from Bus Controller/Bus Master systems wherein only a single node is responsible for controlling multiple-transmitter bus access, even if that access may be within a cyclical schedule (an example being MIL-STD-1553).

multiple vs single access[edit]

Periodic multiple-transmitter time-triggered protocols are naturally distinct from periodic single-transmitter messaging protocols, ARINC 429 being an example of the latter. In the ARINC 429 protocol, exactly one transmitter is connected to the bus, thus avoiding requirements for multiple access techniques. Also, even though individual ARINC 429 messages are transmitted on periodic static schedules (within the maximum and minimum transmit intervals for each label), multiple labels on a bus are not necessarily collectively scheduled into a larger logical cyclic frame or major cycle. The specification of a single ARINC 429 label message includes its periodic timing, but not its timing relative to other labels that may be in the same channel[2] (although such cyclic effects may be a natural consequence of the implementation of the particular labels for a given channel).

static vs dynamic schedule[edit]

The safety-critical isochronous time-triggered protocol schedules are static (a priori) schedules as opposed to dynamic or auto-negotiated (ad hoc) schedules. That is, the a priori time-triggered schedule is typically predefined and qualified before operation, whereas ad hoc time-triggered schedules can be made up "on the fly" cases as of USB networks, which include auto-negotiated, plug-and-play, isochronous mode.


Examples of time-triggered communication protocols include:[3]

  • ISO 11898-4, CAN Time-Triggered Communication (TTCAN)
  • SAE AS6802, Time-Triggered Ethernet (TTEthernet); effectively, time-switched ARINC 429 channels over Ethernet
  • SAE AS6803, TTP Communication Protocol (TTP), SAE standardization of TTech's proprietary time
  • FlexRay
  • AUTOSAR Virtual Function Bus employs logical time-triggered Flexray frames, which are virtually or physically transported as Flexray frames or as shorter segments over other low-level protocols; e.g., CAN, LIN
  • ARINC 825, General Standardization of CAN Protocol for Airborne Use[4]

See also[edit]


  1. ^ Cite error: The named reference ObermaisserPara was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference ARINC429 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference ObermaisserComm was invoked but never defined (see the help page).
  4. ^ Knueppel,, Ralph (2012), "Standardization of CAN networks for airborne use through ARINC 825" (PDF), CAN in Automation, CAN in Automation  Missing or empty |title= (help)


Time-triggered CAN, CAN in Action (CiA)






{{SAE standard
 |     id = ARP4754A
 |  title = Guidelines For Development Of Civil Aircraft and Systems 
 |   date = December 2010
 | author = SAE International
Guidelines Covering Aircraft Development and Operation
Safety Assessment in Development
Aircraft & System Development
Safety Assessment in Service

The objective is to use an adaptation of Figure 1 of ARP4754A to visually link the integrated SAE and RTCA standards. There is probably a better way to do this; so someone with more template or svg skills is welcome to improve. The overall plan is to use the template to visually link the guidance documents that have been integrated under AC 1309 and ARP4754. For this reason I wanted to

  1. replicate the spirit of Figure 1 in an infoboxish style and
  2. integrate links to the included document articles (something of a Nav box?).






{{RTCA standard
 |     id = [[DO-178C|DO-178C / ED-12C]]
 |  title = Software Considerations in Airborne Systems and Equipment Certification
 |   date = 01/05/2012
 | author = RTCA SC-205<br>EUROCAE WG-12
{{SAE standard
 |     id = ARP4754A
 |  title = Guidelines For Development Of Civil Aircraft and Systems 
 |   date = December 2010
 | author = SAE International

ISO 26262[edit]

Comparison of Hazard Effects Level
ASIL Severity Classifications DAL Failure condition Passenger threats Crew threats Airplane capability or safety margin
- - A Catastrophic Loss of the airplane and death of all aboard Fatality or incapacity Hull loss
D Life-threatening (survival uncertain) to fatal injuries
B Hazardous Serious or fatal injuries Impared abilty Large reduction
C Severe to life-threatening (survival probable) injuries
C Major Distress or minor injuries Distraction Significant reduction
B Light to moderate injuries
D Minor Physical discomfort Flight change or emergency procedures Slight reduction
QM No Injuries E No Effect Inconvenience No Effect No Effect


In particular, Russia and North America are the homes of great mechanized granaries, known separately and more conventionally as grain elevators.

Planet of the Apes[edit]

In a background subcontext, television and newspaper media report the launch and subsequent loss of the Icarrus mission to Mars. Ceasar's parable with the sticks refers to the Roman and Italian symbology of the Facsise Rise makes several references to the Bright eyes was both the name of Ceasar's mother and Dr. 's ... name for Taylor The general layout of the ape cages in Rise reflect the layout in PotA Both Ceasar and Taylor are hosed down in punishment. Ceasar's first word is "No" in both Rise and PotA 's line "its a mad house! It's a mad house"


B9 was originally defined by its neutritional effects, tha tis if there is not enough B9 factor tissue that depends on rapid cell devision fail. Such tissues include skin, hair, blood cells, intestinal linings and cancerous tumors) Vitamin B9 refers to a particular essential nutritional factor. Absence or suppression of the B9 factor results notably in slowing or failure of rapidly dividing cells (e.g., blood, skin, hair, intestines, or cancers), but also results in elevation of homocystine [5] and problems with nerve function.[6] Chemically, all B9 vitamers have the same parent structure, which is named pterolymonoglutamic acid (PMGA). Plants and bacteria are able to form this stucture de novo from pterin, p-aminobenzoate (PABA), and glutamate moieties [Biosynthesis of Folates] but vertebrates lack a complete folate synthesis pathway and so need a dietary supply.[7][8][9]

The terms Folic Acid and Folates are both used interchangably to refer to all natural and syntheric compounds that function as B9. However, there are situations where either term is used more narrorwly. Folic Acid can be used to refer generally to all compounds based on PMGA; but it can also refer specifically or implicitly to the manufactured "crystaline" form of PMGA, particularly as used in supplementation. Folate can also be used to refer generally to all compounds based on PMGA; but it is also used to refer specifically to PMGA-based compounds arrising through biological processes, especially the folate metabolism. The distinction between "crystaline" PMGA and bological folates is important because the to forms have different biochemical properties and effects.

FA prefered syn FA all PGMA FA food supplement F prefered syn F all natural

however, The prefered synonym for pterolymonoglutamic acid is folic acid, however there is some difficulty here because in some literature folic acid refers specifically or implicitly to the manufactured "crystaline" form of PMGA while other literaure applies the term equally to any metabolic compound, natural or synthetic, having pterolyglutamate as a parent structure.

  1. ^ Obermaisser, Roman (2005). Event-Triggered and Time-Triggered Control Paradigms. Springer Science+Business Media. pp. 21–23. ISBN 0-378-23043-2 Check |isbn= value: checksum (help). 
  2. ^ Obermaisser, Roman (2011). Time-Triggered Communication. CRC Press. ISBN 978-1-4398-4661-2. 
  3. ^ ARINC Specification 429, Part 1-17. Annapolis, Maryland: Aeronautical Radio, Inc. 2004-05-17. 
  4. ^ FlexRay Communications System Protocol Specification
  5. ^ "Folate: Evidence". Health Information - Drugs and Supplements. Mayo Clinic. 
  6. ^ Stahl, Stephan M., M.D. Ph.D (2008). "L-Methylfolate: A Vitamin for Your Monoamines". Journal For Clinical Psychiatry. 5. 70: 767; author reply 767–9. PMID 19193337.  Unknown parameter |month= ignored (help)
  7. ^ Goyer, Aymeric; Victoria Illarionova, Sanja Roje, Markus Fischer, Adelbert Bacher and Andrew D. Hanson (2004). "Folate Biosynthesis in Higher Plants. cDNA Cloning, Heterologous Expression, and Characterization of Dihydroneopterin Aldolases". Plant Physiology. 135:103-111. PMID PMC429337 Check |pmid= value (help).  Cite uses deprecated parameter |coauthors= (help)
  8. ^ Bauer, Stefanie; Ann-Kathrin Schott, Victoria Illarionova3, Adelbert Bacher, Robert Huber, Markus Fischer (2004). "Biosynthesis of Tetrahydrofolate in Plants: Crystal Structure of 7,8-Dihydroneopterin Aldolase from Arabidopsis thaliana Reveals a Novel Adolase Class". Journal of Molecular Biology. 339 (4): 967–979.  Unknown parameter |month= ignored (help); Cite uses deprecated parameter |coauthors= (help)
  9. ^ Fischer, Markus. "Biosynthesis of Folates".