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Thread: RS232 control of Harman Kardon AVR635

  1. #1
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    Jan 2005
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    Default RS232 control of Harman Kardon AVR635

    The HK AVR 635 has a bi-directional protocol.

    Well, the receiver continuously blasts over the RS232 port the contents of its front panel display. Commands have a prefix "MPSEND" and a checksum check word at the end.

    Anyway, I'm trying to figure out whether I can use this with Girder, or whether I have to write my own application to read the RS232 port. Seems like it would have to continuously wake up to read the state and stuff it into some state variable, though.

    Any ideas?

  2. #2
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    You should be able to do this with Girder, the Serial plugin and LUA (state) variables. Others have used Girder to auotmate their AVR525s and other receivers.

    Could you supply a link to the RS-232 protocol document for the AVR 635? (or attach a .zip file containing the document here) This would allow me to help you more.
    Mark F

  3. #3
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    Sep 2005
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    Default

    Trying to resurrect this thread, as I'm not having much luck getting Girder to communicate with my 635. I've attached the word .doc that supposedly "explains" the necessary settings, but it's mostly Greek to me. I can see what the port settings need to be, but beyond that (transmit and receive tweaks) I am totally lost. Any help would be much appreciated.

    p.s. If possible, please explain what the LUA (state) variables pertain to (I'm a Girder newbie). Am I correct that they are only needed if one wants to interpret feedback from the AVR?
    Attached Files Attached Files

  4. #4
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    This shold be controlable from Girder. You will need to compute a checksum to add to commands. We can help you getting this working with G4 but not G3.3

  5. #5
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    Default

    Quote Originally Posted by Mike C
    We can help you getting this working with G4 but not G3.3
    Meaning its not possible with G3.3, or that you no longer support it? Any further tips on computing the checksum (not even sure what that means ops: ) would be much appreciated.

  6. #6
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    Quote Originally Posted by aok
    Quote Originally Posted by Mike C
    We can help you getting this working with G4 but not G3.3
    Meaning its not possible with G3.3, or that you no longer support it? Any further tips on computing the checksum (not even sure what that means ops: ) would be much appreciated.
    We still support 3.3 but are not longer adding any additional functionality. Its doable on 3.3 though. The protocol requires you to compute a checksum which is used to make sure the command is good.

  7. #7
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    Quote Originally Posted by Mike C
    The protocol requires you to compute a checksum which is used to make sure the command is good.
    I'm sorry to be so dense, but if you have a spare moment can you point me in the direction of any documents, links, etc. where I might be able to educate myself on what this means, in specific terms, for how to configure Girder correctly. I'd rather stick with Girder 3.3 for now (I'm primarily an Xlobby user, which may have its own RS-232 functionality in the near future, and I'd rather not buy Girder 4 for one small thing I will no longer need).

    Bountiful thanks for your time.

  8. #8
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    Default gave up on RS232 control for 635

    Apparently the 635 sends a continuous stream of data out of its RS232 port, always showing the front panel state of the device.

    However, Windows XP Pro, when booting, attempts to do device detection on its RS232 ports to see if there is a serial mouse or some other device connected, and the continuous stream of data from the HK 635 seems to have confused it -- my system would crash and it would go into a reboot cycle. So, to reboot the computer, I'd have to detach the 635 first.

    On reading the data from the 635, you can ignore the checksum. On writing data to the 635, you can precompute the checksum, but I wasn't successful.

  9. #9
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    Default Re: gave up on RS232 control for 635

    Quote Originally Posted by lmm
    Apparently the 635 sends a continuous stream of data out of its RS232 port, always showing the front panel state of the device.

    However, Windows XP Pro, when booting, attempts to do device detection on its RS232 ports to see if there is a serial mouse or some other device connected, and the continuous stream of data from the HK 635 seems to have confused it -- my system would crash and it would go into a reboot cycle. So, to reboot the computer, I'd have to detach the 635 first.

    On reading the data from the 635, you can ignore the checksum. On writing data to the 635, you can precompute the checksum, but I wasn't successful.
    strange

    I wonder if that would happen if you connected via a usb -rs232 dongle?

  10. #10
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    Sep 2005
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    How about booting the computer when the 635 is powered off? In any case, I haven't experienced the same problem and I'm also running XP. Is it also possible that you have the wrong kind of cable (you don't want a null-modem cable, you want a straight through DB-9 male to DB-9 female RS232 cable like one of these.

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