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Thread: Can't run project.

  1. #51
    Yes, there is an oscilloscope.
    Peak value of voltage 3.29V.
    Voltage rise rate <1.00 mS
    But I understood your idea. Today I will.
    Last edited by m-16; 04-03-2019 at 08:36 AM.

  2. #52
    Only the chip on the board ...
    Power supply from Teensy stabilizer:18 - 3.30V
    Power supply from a laboratory power source: 18 - 3.30V,
    The next step weighing capacitors.
    Last edited by m-16; 04-03-2019 at 03:55 PM.

  3. #53
    I soldered all the power circuits, step by step.
    Powering them from USB.
    All is perfect, with 3.3 V on pin 18.
    Everything is even more confusing now.
    But it works, and that's a big plus.
    All that's left is soldering MK66 in place.
    But right now, it's a great success.

  4. #54
    Success!
    Paul, thank you so much for the help, I owe you one.
    I loaded the sketch and everything works great!

    My thanks to everyone who participated.

  5. #55
    Senior Member PaulStoffregen's Avatar
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    Glad it's working.

    Any idea what was really wrong? Would really like to know what caused those chips to not output 3.3V on pin 18, since that's one of the very first steps we always recommend for troubleshooting.

  6. #56
    Paul, to be fair, I'm not in a hurry to draw conclusions on the issue.
    One thought is (possibly) static when soldering.
    I will also collect 4 devices, and then we finally summarize.

  7. #57
    Senior Member PaulStoffregen's Avatar
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    Floating pin 18 is a really serious problem. I *really* want to get to the bottom of why this happened. That is why we sent you 5 replacement chips.

    Please, help us and everyone else who might encounter this problem in the future. We really need to understand how this happened and what you and others should do in the future if it ever happens again.

  8. #58
    Required Paul.
    This is without convention.
    Especially since I'm your debtor.
    I already have assumptions and I shall make them later.

  9. #59
    Made a few more assembly device.
    There are no problems, it works.
    For the experiment repeated the conditions of the first assembly.
    Result - MKL4 does not work.
    What were the conditions and what I repeated.
    The first assemblies were held in a heated room, the weather was cold outside. Humidity in the room about 30%.
    At the moment, there is no heating and the humidity in the room is about 64% - the assembly runs without problems.
    I drained the air conditioner up to 32%, the assembly - not luck.
    Do not hesitate to remove statics from a soldering iron and a bracelet.
    So far, only such results.

  10. #60
    Senior Member PaulStoffregen's Avatar
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    I'm a little confused by all this talk of temperature & humidity.

    Are you saying the *same* PCB design sometimes worked and sometimes did not work? Or are all the failures & successes consistent with the PCB design?

  11. #61
    Senior Member PaulStoffregen's Avatar
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    One more question - did you personally solder these chips? If you did not solder the parts, was the work done by someone you personally know? At your location?

    Or did you send the boards to a company to be soldered?

    I ask this because so far, the only known cause of pin 18 floating is when contract manufacturers substitute a non-PJRC chip which is blank. A blank chip will have pin 18 floating.

    If there is *any* other reason pin 18 would be floating, when using a genuine chip from PJRC, I *really* want to understand why that happened.

  12. #62
    Dear Paul,
    Small-scale production, so I personally carried out the entire assembly and soldering.
    At the moment I conclude that the chip was reset by static electricity.
    At this stage I have little information to see some other reason.
    I will do more assembly and collect information to clarify this thread of the forum.

  13. #63
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by m-16 View Post
    At the moment I conclude that the chip was reset by static electricity.
    But you had more than 1 chip fail this way, right? How many chips were tested with pin 18 floating?

    Static electricity from normal handling, even without any ESD precautions, is not a likely explanation for more than 1 chip failing from such a small batch.

  14. #64
    4 chips were damaged and 3 successful assemblies were made.
    1 chip from 4 was damaged by the experiment that I described above.
    3 successful assemblies were carried out one after another at high humidity in the room with all measures for removing static electricity.

  15. #65
    Senior Member PaulStoffregen's Avatar
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    I'm very skeptical that static electricity during ordinary handling of the chip during hand soldering, even in extremely dry conditions, is a plausible explanation for 4 of 7 chips not working.

  16. #66
    So far this is the only explanation that comes to my mind.
    It is possible that it is not.
    Perhaps this is somehow related to the order of assembly.
    The first three assemblies were completed - the chip was soldered last.
    All successful assemblies, the chip was soldered first, power was applied and a check was made.
    The same conditions were in the experiment. The chip was the only one on the board and power was applied, the result was not luck.
    But next week, I will acquire another 5 MKL4. While I am not ready to do the assembly with the MKL2.
    I will experiment more.

  17. #67
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by m-16 View Post
    So far this is the only explanation that comes to my mind.
    It is possible that it is not.
    ESD is an extremely unlikely explanation!

    First, failure rates over 50% are highly improbable for an ordinary dry environment. The chip has built-in ESD protection that is usually sufficient for normal handling. Even 1 chip in 7 failing is not likely, but 4 of 7 is extraordinarily unlikely.

    Second, ESD failure tends to manifest as "latch up", where the parasitic transistors in the body of the chip turn on and effectively short the power supply, causing the chip to get burning hot. Short circuits between the pin input circuitry and other parts of the chip are also a probable failure. ESD damage tends to cause shorts. Having a floating pin and no signs of excessive power is a highly unlikely result.

    Something else almost certainly went wrong here. ESD is almost certainly *not* the answer!

  18. #68
    I understand you.
    Ready to drop your conclusions.
    Strange one.
    All destroyed from the first delivery.
    Before soldering, I soldered 3, 4 and 5, 6 and checked 18. It was 3.2V.
    After soldering 0.2 - 0.8. Thermal breakdown? But the chip absolutely did not exceed the permissible heating temperature according to the datasheet - 250 degrees Celsius.
    From the second batch there are 2 and 1 from the first batch.

  19. #69
    All builds are made.
    2 successful with MKL04 from the second delivery
    and
    1 not successful with the chip from the first delivery, which was checked before installation and had a 3.2V on the 18th leg with a 3.3V power supply.
    The chips from the second delivery did not even check.
    Redid the PCB under the chip MKL02, I will acquire them today.

    I have a question, yet this question is off-topic.
    I reviewed the entire forum, but did not find the answer.

    Is it possible to somehow change the CPU Clock programmatically and reduce the clock to reduce battery consumption, say, from the 72MHz frequency clock to 48 or 24 MHz?

  20. #70
    Senior Member PaulStoffregen's Avatar
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    Sounds like you have not been able to diagnose the problem which caused those chips to fail?

    Please start a new thread for any unrelated question. I want to keep this one focused on **WHY** you experienced a problem where pin 18 (Program) appeared to be floating. That is a very serious issue, because the only (so far) known cause is an unprogrammed chip, or the pin not soldered.

  21. #71
    Yes.
    I understood you.
    So far, I am only stating that all the chips from the first delivery did not work.
    Only 1 of the second delivery did not work, apparently was spoiled by me.

  22. #72
    Good evening.
    Collected 5 more devices.
    There is no problem with the launch.
    Let me summarize this thread.
    All chips of the first part were clean and not writed by the bootloader.
    For this, Paul, thank you very much for the great help that you have provided by correcting the situation.

  23. #73
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    This is amazing.. I have yet to have any bad loader chips when used in pre-production boards that I soldered components on. I have done a few.. over 25 if I recall.
    The only issue that the schematic software that I used to make the PCB pulled the wrong foot print for the IC. This has happen 2 times now..
    Looking for a better software now other than Diptrace..

  24. #74
    Yes, I understand everything, but the problem is that the printed circuit board has not changed, from the first assembly to the last.

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