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RTOS/LAUNCHXL-F28069M: Device destroyed

Stark
Intellectual 420 points
Part Number: LAUNCHXL-F28069M
Other Parts Discussed in Thread: CONTROLSUITE

Tool/software: TI-RTOS

Hi,

I wanted to read ADC value from pin 27(ADCINA0) on J3 pin and I have input +5V from the same J3 pin 21 and wanted to blink LED accordingly. I dont understand why my device stopped working. This is the second time I think I destroyed my device. When i am connecting, its making little noise and then all the LED goes off.

Any idea how to FIX this?

regards

Rahul

  • 0
    TI__Guru 62975 points
    Rahul,

    F28069 is not 5V tolerant. The valid input voltages are typically 0V to 3.3V. Driving 5V to any F28069 pin may permanently damage the device.

    The 5V supply is included to power other circuitry and to maintain compatibility with BoosterPacks that use 5V for power.

    -Tommy
  • 0 in reply to tlee
    Intellectual 420 points
    Hi Tommy,

    Is there any way to fix it by replacing IC or it is already a piece of crap?

    thank you

    regards
    Rahul
  • 0 in reply to Stark
    TI__Guru 62975 points
    Rahul,

    It depends on the level of exposure to 5V. A short, momentary exposure usually limits the damage to the pin. A prolonged exposure may burn out more critical circuits within the F28069.

    If ADCINA0 is the only pin exposed to 5V, it is likely that the F28069 is the only component that sustained damage. I would suspect that the PCB and other board components are fine. You should be able to check on the LEDs for the power supplies and XDS100 to confirm that they are working as expected.

    -Tommy
  • 0 in reply to tlee
    Intellectual 420 points

    Hi Tommy,

    Thank you for explaining. 

    I still have one question to ask. I have motor with Resolver as a position sensor. The signals that I will get from resolver are sin&cos with maximum voltage amplitude 10V pp. See the attachment. 

    If launchpad (specifically ADC) can only bear max upto 3.3V then how do I read these signals with higher voltage with ADC pins? because I have to have these signals to be converted in to digital value for position feedback.

    regards

    Rahul

  • 0 in reply to Stark
    TI__Guru 62975 points
    Rahul,

    Op-amps can be used to reduce and offset the voltage into the 3.3V range. You can see the TMDSRSLVR_v1.0 schematic in controlSUITE for reference.

    -Tommy