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JVM error — Parallax Forums

JVM error

Dan DavisDan Davis Posts: 18
edited 2008-02-23 18:45 in General Discussion
I get these kinds of errors on occasion:

[noparse][[/noparse] Error IDE-0042] Unknown unhandled exception in JVM (736).

Any good way to go about troubleshooting these?

Dan

Comments

  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2008-02-22 23:19
    Does this error occur consistently with your program, or does
    it occur, and then after you reset the javelin it sometimes does not occur ?

    Are you using a Board of Education USB ?

    regards peter
  • Dan DavisDan Davis Posts: 18
    edited 2008-02-22 23:24
    It is not consistent. I did reset a few times and it goes away.

    It's in a breadboard. I've created my own interface to use it with my serial port.

    As I was running the test again I got these errors:

    [noparse][[/noparse] Error IDE-0015] Stack trace is corrupt.
    [noparse][[/noparse] Error IDE-0024] Unknown bytecode in the JEM file (dup_x2).


    I'm curious why you ask. Do you think my serial connection is flaky?

    Thanks,
    Dan
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2008-02-22 23:36
    It could be, because it looks like the erratic behaviour that is
    sometimes present on a USB connection.

    What brand/type of PC do you use? There were 3 threads recently
    reporting serial port issues on Dell PC's.

    Can you use the function Terminal.getChar?
    Try attached program.

    regards peter
    java
    java
    TerminalTest2.java
    2K
  • Dan DavisDan Davis Posts: 18
    edited 2008-02-23 00:01
    Funny you should mention it. I indeed have a Dell. Precision 380 to be specific. Pentium D 2.8GHz (dual-core).

    What am I doing with this program? It appears to work. When I type a character it prints "received character {0xXX}"

    Dan
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2008-02-23 00:11
    You need to type one of the commands
    help· clear· bell cmd· flash
    followed by enter.
    If the javelin receives the command correctly it will perform the function.

    See this thread about the Dell PC's.
    http://forums.parallax.com/showthread.php?p=702197


    regards peter
  • Dan DavisDan Davis Posts: 18
    edited 2008-02-23 00:17
    It works. If you are 99% confident that the errors have everything to do with my PC, and that it wouldn't be encountered while the chip is running standalone, I will just deal with it. I just don't want the program to crash in production.

    Dan
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2008-02-23 04:03
    You mentioned a breadboard.
    Does that mean you have the javelin in the breadboard, then use wires
    from javelin pin1-pin4 to a DB9 connector, then a straigth DB9 cable to your
    PC com port?

    I have read in several post on the propeller forum that breadboards
    have quite a capacitance on their connection holes. This, or a bad
    connection, can cause these occasional errors. If possible, put in
    a DIL24 socket first, with wires soldered to its pins 1-4 that
    go to the DB9 connector. Then at least you know the
    connections to your PC com port are ok. Then put the
    javelin in the DIL24 socket.

    regards peter
  • Dan DavisDan Davis Posts: 18
    edited 2008-02-23 17:28
    The Javelin is in a breadboard, with wires pointing upward and clips attached from the serial cable.

    I'm not sure I could buy the capacitance thing. If there was any it's probably down in the picofarads. With a maximum possible frequency of ~38kHz, the reactance would be no less than 600k. I could be wrong but I would consider this sufficient enough to keep the lines separate.

    But, since you bring up serial line corruption, I did have a problem with RF interference at the beginning of the project that I thought I had nailed, I can try an experiment to eliminate that possibility.

    Thanks again for the info, the original error message didn't mean anything to me, at least I have something to work off of.

    Dan
  • Dan DavisDan Davis Posts: 18
    edited 2008-02-23 17:49
    Peter,

    Even if I get an unhandled exception, do you have a list of the error numbers, and would it be of any use to me? I just received an 812, I get several different numbers.

    Dan
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2008-02-23 18:16
    The list with error numbers are in this thread:
    http://forums.parallax.com/showthread.php?p=550606

    The number specified by Unhandled exception is the address at which
    a class header should be located but isn't, which makes me believe
    the error received is not the right value. This kind of errors
    can occur with a bad serial connection,· even if download and Identify
    appear to work.

    Do you have a parallax usb2ser cable that you can try?
    This at least solved the serial port problems on Dell PC's for other users.

    regards peter
  • Dan DavisDan Davis Posts: 18
    edited 2008-02-23 18:45
    I do not, but if that seems to be the problem, I'll order one today. Thanks for your help.

    Dan
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