7
rfc7168
3y

Fried two devices today by simply connecting them to a power source.

Changed nothing in the circuitry, no shorts due to solder residues (a simple modification was made), no changes in the input parameters. Check.

The afromentioned devices should have only minor HW changes compared to a previous version I'm working with and as far as I can see absolutely nothing which should cause the damn microcontroller to release smoke like a steam train. (All right, a very miniature steam train.)

So the only significant difference might be the firmware which I didn't check yet but will tomorrow. Not my code and the corresponding IDE just basically sucks. Yay.

On the other hand, the Software part finally feels like I'm getting somewhere. It seems just ... to work. Very suspicious.

Feeling ambivalently frustrated and relieved at the same time. Sigh.

Comments
  • 1
    @Condor Nah, it didn't. :) - Both devices did work without the modifications, though.
    (And the circuitry at this point is exactly the same as in the previous version so - argh!)
  • 1
    Could it be that some input storted the supply voltage to ground due to firmware changes?
    (or some times MOSFETs create a short because of ESD)

    To prevent this kind of risk, you can put in a >10k resistor in series of the data lines. 😉
  • 1
    Yup. That's what I'd like to find out today, because there was in 1/2 nothing but a power supply connected.

    (ESD is rather unlikely - handling and packaging were sufficient to prevent most ESD events.)
  • 1
    @nin0x03 hmm... maybe one of the pins was configured as output with default value 0, so the supply got shorted through the microcontroller...
  • 1
    @PonySlaystation I'd wished, because that'd have been easy, but no.
    (What is most likely right now is a component change I wasn't aware of. Because fuck documentation or who cares diffing two BOMs somewhere anyway, I think. Grah. 😤)
  • 1
    @PonySlaystation Jup, component changed. Two pins swapped: VIN and VOUT. m(
  • 1
    @nin0x03 oh 🙈 thx for the update 😎
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