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Alpine AINet CRC solved

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  • Alpine AINet CRC solved

    If anyone is still interested in AiNet interfacing, I have solved the CRC problem.
    The AiNet bus physical layer is very similar to the SAE J1850 PWM specification.
    I have been investigating the bus and have loged most, if not all, messages between the HU and CDC.
    I was originally working with Jaguar HU and CDC (thats what I want to interface to) but now also have a standard Alpine HU and CDC and have been loging thase messages as well.
    While I have not fully decoded the messages I have done enough to complete my project (CDC emulator) but will continue and see if I can decode more.
    If anyone is interested I can post my findings (after I make them more presentable).


  • #2
    Humm, very interesting! I don't have any Alpine system, but I would buy one if I knew more about it.

    Can you post your findings, or some of it?
    Worklogs: 08 Sequoia Platinum Carputer (In Progress!)
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    • #3
      Wow that's cool this has been a long time coming. I remember that invravee guy solved it but he wouldn't share his info. Anyway, kudos.


      • #4
        This sounds like a significant development. Good work on cracking the CRC.

        A good number of folks are using Alpine DSPs for their output stage - such as the PXA H701.

        It would be fantastic to control basics such as volume from the PC without having to use an Alpine HU or remote.

        Does your breakthrough open up the possibilities for PC control of the PXA H701?

        If so, I would gladly denote some greenstuff to support the work.


        • #5
          Hi Tony,
          I don't have a PXA H701, so I can't look at the commands, but if it can be controlled over the AiNet bus I can not see why it would not be possible to do as you ask.

          The only hardware I have is the Jaguar HU and CDC plus Alpine CDA 7839E HU and CHA 1214 CDC, so all my work to date relates to this hardware.

          I will have a look and see if I can pickup a PXA H701 or similar on ebay at a resonable price (although I have no idea what that would be) and have a look at it (No promises though).

          I suspect that now we know how to calculate the CRC byte, that other people more familar with controlling this equipment from PC'S will be looking into it.



          • #6
            Hi Colin,

            Thanks for your reply. Where are you based? - I would be happy to take out my PXA-701 and controller to get the ball rolling - just to see how similar the protocols are etc..


            • #7
              Nice offer Tony, but I am Sydney, Australia.
              You could always come out for a holiday.


              • #8
                Would you know, I took the family out to Australia in November and December. Sydney, Blue Mountains, Daintree and Cape Tribulation, Port Douglas, Kewerra Beach, Hervey Bay (Whale watching), Noosa and Brisbane.

                Loved it. Another two months "on location development" would go down very nicely...

                I bet it's around 30+ degrees C at the moment. Its around freezing here, and we're just off for a rugby match (both boys play).

                I wonder if anyone on this forum is nearer? anyone??


                • #9
                  And I was in the UK in September november. Yes lovely here today about 35C. Enjoy the football.

                  I am just working on tidying up some of this Ainet info so I can post it, hopefully tomorrow.


                  • #10
                    Subscribed and bookmarked


                    • #11
                      I have attached ( I hope) a pdf document with more information about my investigation of the AiNet bus.
                      This not complete and I will update as more info and time becomes available.
                      Hopefully there is enough info here to get some other people started as well.
                      If anyone wants any specific info I have not include yet, please let me know.


                      21/01/2009 Have made additions to attachement, please see later post.


                      • #12

                        I can see an awful amount of work has gone into this solution already. Given my age, it's nice to see some real logic circuits, as it allows you to grasp the AINet function.

                        I can see a PIC-based AINet to RS232 box becoming the friend of many on this site.

                        I've done this before with a VW head unit and Girder - using Girder to capture the serial streams from a HU button press - whilst the "housekeeping" data has been filtered.


                        • #13
                          Did you know anything about the Navigation Cabel and the RGB input?

                          The main question is for me, will alpine transfer the ,,touch" position from a headunit to the navi via AiNet Protocol or use they anything else?

                          the idea behind is to use a alpine wgva monitor for output the pc screen and use the touchscreen for mouse control.

                          i find the following things for now:

                          - your AiNet Protocol
                          - Vga2RGB TTL Converter


                          • #14
                            Must say I'm suprised to see this thread not capturing more interest.

                            I know there is a large PHA H-701 userbase, who I'm sure would love to control the basics through a PC and not the RUX controller.

                            So, I'm bumping to see who else gets this...

                            Colin, any luck with a PIC based unit?


                            • #15
                              Hi Tony,
                              Sorry I have not posted anything new for a while, but I have been away for the last three weeks and could not post.

                              I am back now and working on the AiNet project again. I had to change to a PIC24 to get the performance I needed, so I thought I might as well use the hardware CRC generator available in the PIC24. Well it sounded like a good idea at the time, but I am having a hell of a time getting it to work, may have to go back to firmware CRC generation (it works fine, but is a bit slow).

                              I am hoping the PIC24 will allow me to do all the work in the PIC with minimal external hardware, and have finalised the PWM code for tranmission and will be starting on the receiving code shortly.

                              Hopefully I can post an update in the next week or so.