Need Help

Discussion in 'Off Topic' started by vivitern, Nov 14, 2017.

  1. vivitern

    vivitern Member

    The mod suggested in the link will not change VCC of the CPU, just the voltage of the analog supply pin and maybe some other points on the board. So the CPU will be outside of the allowed voltages. If you really want to change VCC to 5V, you would have to do a similar mod on J22. But I would not do this before checking if all other parts on the board can take the 5V instead of 3.3V AND there will be no parts left hanging on 3.3V, getting a 5V signal from the CPU.
    I would not risk to fry my DK for just simply getting a 5V range, a small board with a few OPAs, or one OPA plus some resistors more should do the job.
  2. Jackson

    Jackson USA member at large

    mozquito1 likes this.
  3. mozquito1

    mozquito1 Well-Known Member

    I thought you needed help, but it sounds like you answered your own problem.
  4. dragger201

    dragger201 If it ain't broke, don't fix it??? You kidding?

    Glad I could help, Vivitern.................
  5. Gyro Doctor

    Gyro Doctor Electronics Tech for over 45 years

    :rolleyes: ... You cannot normally just run any 3.3vdc MCU or CPU on 5vdc and expect proper scalar functionality even if it and other parts can accept
    the higher voltage. If it doesn't just fry parts, internal clocks (including the WDT) as well as any other pulse parameters, peripheral controls,
    and coms will still run awry.

    To adapt running a 3.3vdc MCU in a 5vdc (and higher or lower and even fluctuating) environment typically a filtered buck/boost converter or
    a simple low dropout Vreg is employed with ample high frequency blocking and large stability capacitance, such as in a tuned Pi filter. ;)

    All this talk of CPU/MCU overvoltage driving is just nonsense because the mentioned "5 volt range" (whether it be the native drive or some external
    monitor) is simply a function of either proper drive conditioning or ADC prescaling and has nothing at all to do with whether you can get away with
    overating chip voltages. Sensory inputs, such as ADCs can be easily scaled for 5, 50, 500 vdc with any 3.3vdc core. :cool:

    It is also evident, by the slinging of terms like "DK" and "OPA", that you guys are: A.) Arduino heads .... B.) On the wrong frikkin forum ... :p
    mozquito1 likes this.

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