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Unable to connect to Javelin Stamp — Parallax Forums

Unable to connect to Javelin Stamp

WaldoDTDWaldoDTD Posts: 142
edited 2008-06-10 14:35 in General Discussion
Ok so my microcontroller stopped working, I am getting an IDE error 0056, I am connecting to the board using a USBto232 adapter and using a BOE Rev C. I was testing a transistor circuit by hooking the Vdd to the base and Vss to the Collector and then a motor between the emitter and the ground. When I turned off the power the transistor was still plugged in and there is a possiblity that there could have been some backflow because there was no protection diode in parallel with the motor. The board however still turns on (LED turns on when thrown to switch 1 or 2) I uninstalled the IDE then reinstalled to version 2.0, I cleaned out the FTDI drivers and downloaded the VCP driver for Windows XP then reinstalled the Virtual COM port on the machine. I then added the COM port to the IDE, there was a loopback showing a potential Javelin but it was unable to reset. What should I do? Is my stamp burned out? THank you-Adam

Comments

  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2008-06-09 07:57
    Do you also get an·echo?
    Do you measure 5.0V (Vdd) at javelin module pin 21 (Vss is pin 23) ?

    regards peter
  • WaldoDTDWaldoDTD Posts: 142
    edited 2008-06-10 01:08
    No echo, no voltage across the Vdd and vss
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2008-06-10 01:30
    Looks like the onboard regulator of the javelin module is defect.
    Assuming the board power is present (power led is on you said),
    you can try to power the javelin via its pin 21 (Vdd).
    Disconnect javelin module pin 24 (Vin) from the DIL24 socket.
    Apply 5V (Vdd) to javelin module pin 21.
    See if you can get echo and status that way.

    regards peter
  • WaldoDTDWaldoDTD Posts: 142
    edited 2008-06-10 02:21
    should I disconnect pin 21 as well or can i just make a bridge over from the vdd board socket? Thanks-Adam
  • WaldoDTDWaldoDTD Posts: 142
    edited 2008-06-10 02:50
    i turned it on patching from the header for the appmods, there was no echo
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2008-06-10 08:08
    I think your javelin is gone. You could send it to Parallax
    so they can check out what exactly is defected. I think
    it is both the regulator and the SX48 chip.

    regards peter
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-06-10 14:35
    Waldo,

    My thoughts from looking at your first post are that you drew too much current from the Vdd line trying to drive the transistor directly. A transistor will draw current from the base proportional to the load current, however, without a current limiting resistor the transistor may fail drawing excessive current from the Vdd line and damaging the Javelin on-board regulator. Of course, as you hinted at, without back-EMF protection there is always the possibility of damage to the transistor from the other side, which could in turn cause excessive current draw from the Vdd line. As Peter said, you can contact us directly and refer to this forum thread. We can have the module sent in for testing and let you know your options. At worst we could offer a discounted replacement.

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    Chris Savage
    Parallax Tech Support
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