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msp430g2553 overheating

Brian Averill
Prodigy 50 points

Other Parts Discussed in Thread: ENERGIA, MSP430G2553

When I connect the usb cable to my msp430g2 the power chip and associated LED become hot. Also, before the heat builds up Energia reports this message: "usbutil: unable to find a device matching 0451:f432" when trying to upload a program. I do unplug the usb cable before the msp430 becomes very hot.

To me these symptoms suggest that something has gone wrong with the msp430. If there is a problem with the power components on the board what can be done to fix the malfunction?

Your assistance is most appreciated.

  • 0
    TI__Mastermind 22925 points
    Brian,

    Sounds like there is a short somewhere on the board. If you are willing to do a little hardware debugging, we might could track down what is shorted.

    If you disconnect all the jumpers on J3, does the problem still exist? If yes, it means the issue is in the emulator side, if not, its in the target side.
    Once you determine which side the short is on, measure the resistance between Vcc and GND on that side (if its the emulator side, also measure the resistance between VBUS and GND on the USB connector). Make sure to do this when the device is not powered.

    If you look at all the components on the board, is there anything that is obviously scorched?

    We can debug further from here once you run these tests.

    Mike
  • 0
    Expert 2740 points

    Check that the MSP430 is not plugged in backwards. This could fry the chip.

    Peter

  • 0 in reply to Peter Dvorak
    TI__Mastermind 22925 points
    Brian,

    Any update here? If not, I will close this thread.

    Thanks,
    Mike
  • 0 in reply to Mike Pridgen
    Prodigy 50 points
    I foolishly tried to reply by email11 days ago. Not sure if what I attempted is silly or not.

    Thank you Mike.

    First you should know that I am a novice regarding microcontollers. I am doing this simple online course (EE40LX-Robot) with UCBerkley. This is how I interpreted/followed your instructions.

    1. There is no obvious scorching on either side of the board.
    2. After removing all the jumpers from J3 the overheating problem still exists when the USB cable is connected.
    3. With the USB disconnected and the jumpers removed I measured the resistance between the VCC pin on the emulator side of J3 and TP3 (which I understand from the MSP430g2 schematic is GND); the resistance is 6.5 ohms.
    4. There appears to be no resistance between VBUS (TP1) and GND (TP3), that is the ohm meter shows no change and displays 1, which seems to be the default display.

    I am not confident about my understanding of the MSP430g schematic.

    Again my thanks - brian
  • 0 in reply to Brian Averill
    Guru 74080 points

    Brian Averill said:
    There appears to be no resistance between VBUS (TP1) and GND (TP3), that is the ohm meter shows no change and displays 1, which seems to be the default display.

    With "no resistance" you mean infinite resistance, I guess? The "1" sounds like this.

    Do you have a program running on the MSP?

    Brian Averill said:
    After removing all the jumpers from J3 the overheating problem still exists when the USB cable is connected.

    But in this case the MSP is not powered. Is it the processor that gets hot or something on the emulator side of the board? Is it the MSP-EXP430G2 you're talking about?

    Edit:

    It is, you said that here:

    Brian Averill said:
    msp430g2

    But what does that mean?

    Brian Averill said:
    When I connect the usb cable to my msp430g2 the power chip and associated LED become hot. [...] I do unplug the usb cable before the msp430 becomes very hot.

    Are both getting hot?

  • 0 in reply to Dennis Eichmann
    Prodigy 50 points
    1. Before the over heating problem began, there was a program loaded onto the msp430.
    2. On the emulator side only the 'power on' LED and very, very close components become hot.
    3. Nothing becomes hot on the msp430 processor becomes hot.
  • 0 in reply to Brian Averill
    TI__Mastermind 22925 points
    Brian,

    Sorry for the delayed response (due to the holidays in the US). It seems like something in the power circuitry on the eZ-FET side is shorting or has blown (causing a short). This is pulling a significant amount of current overheating some of the components. Try looking at all the solder joints (through a magnifying glass or microscope if possible), and see if there are any visible shorts. You could try replacing components, but at some point, its just easier to get a new board.

    Did this board ever work, or has it failed from as soon as you opened the packaging? Did you make any hardware modifications (or connections) to the board before the failure occurred?

    Mike
  • 0 in reply to Mike Pridgen
    Prodigy 50 points

    Yes, the board worked for approximately 20 uses while testing circuits for the robot that I was attempting to build. Under a 5x magnifier there are no obvious shorts visible to me. I have been using an Arduino for 2 years without problems; the TI board seemed quite attractive from the specs, but now not sure if I should proceed with another msp430g2553 even though it is inexpensive.

    Thank you for your replies these past few weeks.

  • 0 in reply to Brian Averill
    TI__Mastermind 22925 points
    Brian,

    You were testing circuits for a robot? How much current were you pulling to test these circuits? The LDO regulator (TPS77301) on the G2 LP that generates VCC only supports 250mA. Is there any chance you pulled too much current? This will damage the regulator and cause the exact issues you are seeing. For robots, motors in particular will pull a lot of current if you stall the motor. However, without know what all your robot does, I can't really speculate what other high current draws would exist in your circuitry.

    Mike
  • 0 in reply to Mike Pridgen
    Prodigy 50 points

    The toy robot, which I had working, consisted of a TI voltage regulator, 2 light sensors, 1 flex sensor, and 2 6v toy motors each controlled by an NPN 100mA transistor (BC547 Fairchild). All the circuits were on a small breadboard with the msp430g as the controller.

    After making the robot work I dismantled the circuits to begin experiments with other circuits. This is when the heat problem began and I believe you are correct that I must have exceeded the 250mA of the LDO regulator. Is it correct to assume that it is pointless to even contemplate replacing the LDO? Perhaps it is best to close this thread/problem OK.

  • 0 in reply to Brian Averill
    TI__Mastermind 22925 points
    Brian,

    If you are handy with a soldering iron (or know someone who is), swapping out the LDO is not very difficult. However, the easiest path is to just get another LaunchPad.

    Just as a note, the LDO on the G2 LP is configured to output 3.6V (it may get updated to 3.3V at some point in the future). If you are trying to drive a 6V motor with this, you are going to get sub-optimal performance on the motors, which may have lead to the high current draw. Also, I generally like to control motors with FETs instead of BJT transistors, as it pulls the gate signal out of the current path, which is a good thing for the MCU controlling the motor.

    Mike

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