Error reading from the serial port (timeout)

wandrsonwandrson Posts: 5
edited 2007-07-25 - 03:56:28 in Microcontrollers
I have a Javalin Stamp on a USB BOE. After programing it with a small test program I tried a quick change and to reprogram it.

I get the following error:

"Error reading from the serial port (timeout)"

The IDE successfully finds the Javalin but programming doesn't work.

I have a LCD AppMod installed and it appears the IDE is successfully reseting the Javalin. The LCD display goes blank when the IDE says reseting. It doesn't display anything else until I hit the reset button and it displays the text from the last program I successfully downloaded.

Any suggestions?


  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2007-04-14 - 18:57:54
    See this thread

    Hit the program button as soon as possible after recycling power to the javelin,
    to prevent the javelin from executing the current program.

    regards peter
  • wandrsonwandrson Posts: 5
    edited 2007-04-14 - 20:57:35
    I just tried this several times, including not powering the BOE until after starting the batch file and I get the same error.
  • Robot FreakRobot Freak Posts: 168
    edited 2007-04-15 - 09:08:55
    Chris Savage said...

    I attempted to cover this issue early on but was assured there were hardware issues. The USB BOE exhibits a known issue on some (rare) computer when a very small program is downloaded into the Javelin. This causes a timeout to occur. The problem doesn't appear to happen when using a Serial BOE with our USB to 232 adapter or when using a straight serial port. It seems to be timing related but what you will need to do is get access to a serial BOE or other development board and connect to a PC which has an on-board RS-232 Serial Port (preferably not a laptop). Try again, and if it doesn't work try the attached Prime Javelin program. Again, this really should be done from a direct serial port on a desktop. In the future avoid downloading very small programs onto the Javelin when using the USB BOE. I hope this helps. Take care.

    Chris Savage
    Parallax Technical Support
  • wandrsonwandrson Posts: 5
    edited 2007-04-15 - 13:45:59
    Thanks for the response.

    I thought that the Javalin was supposed to be compatible with all Parallax development boards.

    This sounds like the Javalin should not be used on USB BOE boards.

    Since I will not purchase another Parallax product given this problem it looks like I have a dead Javalin--since I have no way to reprogram it.

    If I ever do get it reprogrammed--what constitutes a "very small" program?
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-04-15 - 17:49:01

    We’re still working on the problem…It appears to related to timing issues (latency) inherent in the USB to Serial conversion. To some degree even BASIC Stamps are affected by this which is one reason why so many USB to Serial Adapters don’t work on the BASIC Stamp and we created our own. If you contact Tech Support Monday we’d be happy to have you return the Javelin and refund your money. I really hope this isolated issue does not cause you hesitation in buying from us in the future. We have found work-arounds which work quite well for other issues. This one is still being worked on. Take care.

    Chris Savage
    Parallax Tech Support
  • joshjoshjoshjoshjoshjosh Posts: 1
    edited 2007-07-25 - 03:11:22
    Was this problem ever resolved? I seem to be experiencing the same thing. I was able to download several programs to the Javelin on my BOE-USB board, but suddenly can no longer do so. I normally see:

    Discarding packet
    Error reading from the serial port (timeout)

    and sometimes:

    Discarding packet
    Discarding packet
    Possible Javelin on COM3 did not respond.
    Unable to find a Javelin on any port.

    i tried modifying the latency settings, installing new USB drivers, switching to a different machine, and using the PrimeJavelinEEPROM.bat program posted on other forum entries. Unfortunately, none of these work. Do I need to use switch to a serial board with USB converter cable? Is there something else I should do?

  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2007-07-25 - 03:56:28
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