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  • VPW 4X high speed

    Looking for a device that can communicate with the J1850 VPW 4X protocol that GM uses, one that will work with HyperTerminal like the Elm327 devices?

  • #2
    Is this for a commercial or a hobby project?

    We can easily add VPW 4x support to OBDLink. Unfortunately, there are so many other projects on the table that it may take a while, unless someone can demonstrate demand for/put some actual $$ behind this feature.

    Vitaliy
    — OBDLink MX: world's smallest, fastest, most advanced OBD/Bluetooth adapter with SW and MS CAN support. Read the review to learn more.
    — Need to look up a diagnostic trouble code? Try the most up-to-date, free DTCsearch.com!

    You cannot send me a private message using this forum. Use my email instead: vitaliy[@]scantool.net.

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    • #3
      This is for a personal project, but if it pans out, it will allow for reprogramming GM Obd2 Pcms, which then would open up the market.

      I have found one that may work for it, hoping to order soon to test.

      http://www.obdscan.net/APEX.pdf

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      • #4
        Originally posted by planethax View Post
        This is for a personal project, but if it pans out, it will allow for reprogramming GM Obd2 Pcms, which then would open up the market.

        I have found one that may work for it, hoping to order soon to test.

        http://www.obdscan.net/APEX.pdf
        I doubt it supports VPW 4x. This is the only only mention in the datasheet says:

        "Future VPW 4X Enable – can be used to
        control the 4X pin of the MC33390 J1850
        VPW driver"


        There's no mention of a command that would let you switch to 4x.

        By the way, we bought a sample not too long ago and it looks homemade. I would guess (based in part on the "Copyright 2006" text and the hand-assembled look) that Harrison R&D sells fewer than 100 units per year.

        Best regards,

        Vitaliy
        Attached Files
        — OBDLink MX: world's smallest, fastest, most advanced OBD/Bluetooth adapter with SW and MS CAN support. Read the review to learn more.
        — Need to look up a diagnostic trouble code? Try the most up-to-date, free DTCsearch.com!

        You cannot send me a private message using this forum. Use my email instead: vitaliy[@]scantool.net.

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        • #5
          Well according to Dan
          "The VPW 4X has not been really tested, we just don’t have the GM ECU data to allow us to test."

          I have re emailed to find out for sure.

          A device that can enable the 4X Vpw can reflash GM Pcm, which in my opinion be a HUGE selling feature.

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          • #6
            Originally posted by planethax View Post
            Well according to Dan
            "The VPW 4X has not been really tested, we just don’t have the GM ECU data to allow us to test."

            I have re emailed to find out for sure.

            A device that can enable the 4X Vpw can reflash GM Pcm, which in my opinion be a HUGE selling feature.
            Which software would you use for reflashing?
            — OBDLink MX: world's smallest, fastest, most advanced OBD/Bluetooth adapter with SW and MS CAN support. Read the review to learn more.
            — Need to look up a diagnostic trouble code? Try the most up-to-date, free DTCsearch.com!

            You cannot send me a private message using this forum. Use my email instead: vitaliy[@]scantool.net.

            Comment


            • #7
              I am currently developing my own, so far have the rutine for getting the Seed/Key pair.
              Need a few more pairs to hopefully hard code the algo to the app.

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              • #8
                Originally posted by planethax View Post
                I am currently developing my own, so far have the rutine for getting the Seed/Key pair.
                Need a few more pairs to hopefully hard code the algo to the app.
                I see.

                I'm still not sure how you're supposed to switch APEX to VPW 4x mode. Is it some kind of undocumented command?

                Vitaliy
                — OBDLink MX: world's smallest, fastest, most advanced OBD/Bluetooth adapter with SW and MS CAN support. Read the review to learn more.
                — Need to look up a diagnostic trouble code? Try the most up-to-date, free DTCsearch.com!

                You cannot send me a private message using this forum. Use my email instead: vitaliy[@]scantool.net.

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                • #9
                  Originally posted by Vitaliy View Post
                  I see.

                  I'm still not sure how you're supposed to switch APEX to VPW 4x mode. Is it some kind of undocumented command?

                  Vitaliy
                  R&D are currently doing some testing for me and I hope to hear back with in a few days.

                  They are going to be testing the 4X mode.

                  Comment


                  • #10
                    Mc33390

                    According to the PDF writeup, they are using the MC 33390 as their VPW transceiver. While this transceiver supports 41.6Kbps send and received, it only supports block mode in receive mode. While you could flash a PCM while not in 'block mode', its going to take pretty darn long. They will need to use a MC68HC58 as their transceiver. (for example).

                    This part is out of production I believe; therefore, at some point quantities will run out.

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                    • #11
                      Originally posted by beyerch View Post
                      According to the PDF writeup, they are using the MC 33390 as their VPW transceiver. While this transceiver supports 41.6Kbps send and received, it only supports block mode in receive mode. While you could flash a PCM while not in 'block mode', its going to take pretty darn long. They will need to use a MC68HC58 as their transceiver. (for example).

                      This part is out of production I believe; therefore, at some point quantities will run out.
                      The MC33390 is a dumb signal level shifter: it changes 5V logic into 7V and vice versa. What makes you say that "it only supports block mode in receive mode"?

                      Vitaliy
                      — OBDLink MX: world's smallest, fastest, most advanced OBD/Bluetooth adapter with SW and MS CAN support. Read the review to learn more.
                      — Need to look up a diagnostic trouble code? Try the most up-to-date, free DTCsearch.com!

                      You cannot send me a private message using this forum. Use my email instead: vitaliy[@]scantool.net.

                      Comment


                      • #12
                        Originally posted by Vitaliy View Post
                        The MC33390 is a dumb signal level shifter: it changes 5V logic into 7V and vice versa. What makes you say that "it only supports block mode in receive mode"?

                        Vitaliy
                        Besides from waveshaping in 10.4k and not wave shaping in 4x mode, it basically is just a transceiver. What I meant to say was that most of the microcontrollers that you can get with VPW support built in generally allow for 4x read and write; however, most do not support block mode except for read.

                        If that interface is using "built in" VPW support (i.e. HC12/HC11/HC08, etc), then they'd have to do a lot of work to get a 4x block transmit.

                        When it comes to that, a lot of people prefer 68hc58's as it does a lot more than a 33390 can do. Unfortunately, they are out of production so unless you are doing low volumes, you probably don't want to use that in your design....

                        Sorry for the confusion. I let my fingers go alot faster than my brain on these explanation......

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