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IEBus/AV-LAN question

Discussion in 'Gen 2 Prius Audio and Electronics' started by hilore, Oct 11, 2005.

  1. hilore

    hilore New Member

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    I have a few questions about IEBus/AV-LAN.

    Is IEBus/AV-LAN transmition similar to internet tcp/udp protocal?

    Do audio/video signal get encode via IEBus/AV-LAN?

    Is the Prius the only Toyota car line that use this feature to
    communicate to other devices?

    Finally,what does IEBus/AV-LAN packet/data look like?

    --Hilore
     
    #1 hilore, Oct 11, 2005
  2. hilore

    hilore New Member

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    I found some info.

    http://www.interfacebus.com/Design_Connector_IEbus.html


    IEbus Description

    IEBus {[Inter Equipment Bus] is used as an In-vehicle [Automotive] support bus using half duplex asynchronous [Multi-Master] communication with CSMA/CD [Carrier Sense Multiple Access/Collision Detection] for access control. Two differential lines are used; Data+ / Data-. Two modes are defined: Mode 0 uses 16 bytes/frame and runs at 3.9kbps or 4.1kbps. Mode 1 uses 32 bytes/frame and runs at 17kbps [6MHz Osc.] or 18kbps [6.29MHz Osc.]. The IEbus allows 50 units on the bus over a maximum length of 50 meters. The IEbus is a 2-wire bus.
     
    #2 hilore, Oct 11, 2005
  3. DanMan32

    DanMan32 Senior Member

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    Is IEBus/AV-LAN transmition similar to internet tcp/udp protocal?

    No, it is closer to Ethernet, layer 1/2 in the OSI model. What one does with IEBus/Ethernet is the user's business. AVC on the other hand, is Toyota's implementation of the IEBus's use, just as IP/TCP is an implementation of the use of Ethernet. IPX/SPX would be another. AVC adds the remaining OSI model layers to the IEBus.

    Do audio/video signal get encode via IEBus/AV-LAN?
    No. Separate wires handle video from the NAV (RGBS) and audio out of the HU (R+/-)L(+/-), and optionally into the HU through the changer port.

    Is the Prius the only Toyota car line that use this feature to
    communicate to other devices?
    IEBus, no. Others use that too. Don't ask me who though.
    AVC, I believe there is a colaboration between a few manufacturers and electronic audio/video manufacturers.

    Finally,what does IEBus/AV-LAN packet/data look like?
    There are at least 2 threads that discuss the decode of AVC. Try keying on IEBus. One poster in one of the threads decoded the packets using a scope.
     
    #3 DanMan32, Oct 13, 2005
  4. hilore

    hilore New Member

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    Thanks DanMan32,

    Assuming all these devices share the same audio/video wires.
    If I could hear the conversion between these devices,
    would the conversion sound something like this?

    Device A= MFD
    Device B= Radio
    Device C= CD Changer
    Device D= NAV

    Press FM button.
    B to A, I am here. I want the audio line.
    A says quiet everyone, B has audio line.

    Press NAV button.
    D to A, I am here. I want audio & video line.
    A says quiet everyone, D has the audio & video line.

    Press DISC button.
    C to A, I am here. I want audio line.
    A says quiet everyone, C has the audio line.



    --Hilore
     
    #4 hilore, Oct 14, 2005
  5. DanMan32

    DanMan32 Senior Member

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    Actually, I believe the "I am here" conversations are done at startup. Then the MFD/HU knows what devices exist.

    Then, MFD/HU say:
    FM button:
    nothing unless an external audio device was turned on, then HU would request it give up the audio input from the changer port.

    NAV:
    MFD: Oh, NAV, wake up!
    NAV: what? Oh, yes. I am awake.
    MFD: I need the map displayed.
    then the MFD would receive the RGBS inputs and display them. Any touchscreen x/y coordinates are sent to the NAV over AVC.

    The exact details of the communications I am not sure of. Would be great to create a permiscouous mode receiver/decoder to examine the messages.
     
    #5 DanMan32, Oct 17, 2005
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