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Thread: Low Temperature Operation

  1. #26
    Senior Member+ defragster's Avatar
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    Quote Originally Posted by chileflora View Post
    Strange, in their manual there is also the LQFP Pinout...(https://www.pjrc.com/teensy/K64P144M120SF5.pdf)
    Paul built and published on OSH for Beta a K66 Ref board that uses the LQFP pinned version of the MCU. Never seen it mentioned - except for losing USB Host - it seems that could be built with the K64 chip in place? Assuming the bootloader would see it as the same "T_3.5 MCU" chip for programming purposes?

  2. #27
    Senior Member PaulStoffregen's Avatar
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    Teensy is made for DIY electronics, mostly focused on makers & hobbyists. PJRC strives to keep Teensy's price reasonable, even though it's built in the USA and tends to compete against very aggressively priced products like ESP32 and Raspberry Pi. Quite a lot of work goes into each Teensy model to fit as much functionality as possible into the small "Teensy" form factor. Use of BGA and QFN chips is essential to meet those physical size goals.

    We go to great lengths to make a Teensy a high quality product. But product design decisions are a matter of trade-offs. We try to keep the price price reasonable, which means the PCBs and PCB assembly & inspection of both are done to IPC class 2 specs. If you are concerned about the reliability of BGA packages (which have been in very widespread use for many years with excellent reliability), your application almost certainly would require IPC class 3 circuit board manufacturing and PCB assembly, is dramatically more expensive, and maybe even materials and inspection exceeding class 3 requirements?

    https://www.acdi.com/ipc-class-2-vs-...erence-part-1/

    Many people & companies do embed Teensy inside commercial products. But that's not Teensy's main focus.

    If you need a high reliability (presumably IPC class 3) non-BGA circuit board, you're going to have to roll your own. We well MKL02 or MKL04 chips which you can pair with the MK66 processor in LPQF package to make your own PCB - but still leverage all the Teensy software.

    https://www.pjrc.com/store/ic_mkl02.html

    If you scroll down on that page, you'll see a reference PCB using the LPQF MK66 and TQFP MKL04 chip. That PCB alone probably does not meet all IPC class 3 requirements, like "teardrops" on all vias. It's meant only as an example and demonstration (and it's how we verified the larger MKL04 truly does work....)

    I'm sure this isn't the answer you want, but it's the best & most honest answer I can give. I hope you can understand that we make Teensy primarily for makers who desire the most capability in a small size board at a reasonable price. Use of the huge LQFP package and other high-reliability (high-cost) measures that you're seeking would be awesome, but the large size and high price of such a board just would not be commercially viable in this maker market.

  3. #28
    Senior Member+ defragster's Avatar
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    Paul - re p#26 - does that same MKL04 chip support an LPQF MK64 built using that OSH REF PCB?

  4. #29
    Senior Member PaulStoffregen's Avatar
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    Yes, both MKL02 and MKL04 auto-detect which chip you've connected and implement Teensy LC, 3.2, 3.5 or 3.6.

    But Teensy 4.0 is not yet supported by the MKL02 / MKL04 chip. I'm working on that, as mentioned on another thread.


    Quote Originally Posted by defragster View Post
    LPQF MK64 built using that OSH REF PCB?
    But one (hopefully obvious) caveat is MK64 has only a single USB port. Like on Teensy 3.5, the location for the USB host port will be 2 analog signals, not USB host.

  5. #30
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    Here's some links to the stuff:
    A MK64FX512VLQ12 144 LQFP rated -40C-105C for $13

    https://www.digikey.com/product-deta...Q12-ND/4462057

    Paul's board for an example
    https://oshpark.com/shared_projects/XbimUyLX

    And required parts
    https://www.pjrc.com/store/ic_mkl02.html

    Now that's a hobby project !
    Last edited by bicycleguy; 02-05-2020 at 09:39 PM. Reason: guess I was to slow to post !

  6. #31
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    I'm sure this isn't the answer you want, but it's the best & most honest answer I can give. I hope you can understand that we make Teensy primarily for makers who desire the most capability in a small size board at a reasonable price. Use of the huge LQFP package and other high-reliability (high-cost) measures that you're seeking would be awesome, but the large size and high price of such a board just would not be commercially viable in this maker market.
    Well, thanks a lot for a very detailed answer... I am doing it mainly for my personal hobby use (I love designing things...).

    I certainly do not have the expertise to embed a high-frequency microproceessor in a custom-designed PCB (at least not yet)... So I am looking for "reasonable" solutions; now, if it is 20 USD or 50 USD board does not matter that much...

    From you experience, how would Teensy 3.5 versus 3.2 rank in terms of temperature and time robustness (vibration and moisture are relatively minor issues)? and also if we go into comparisons, how would a 2560 board (specifically Robotdyn pro which I was using before) and a Pixhawk rank here?

    I am kind of on a crossroad, because 8 bit microprocessors are really too outdated. I did succesfully make a crossover prototype 2560/RPi which also relied on a secondary AP (Pitlab) - (2560 generates signals which are fed into diversity input of the Pitlab Autopilot, and 2560 receives "intelligent" commands form RPI), but now I am thinking of trying to integrate everything under one umbrella and try to develop custom PCB which would have for the first version complete Teensy boards on it...
    Last edited by chileflora; 02-05-2020 at 10:03 PM.

  7. #32
    Senior Member+ Frank B's Avatar
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    - Ask NXP why they produce BGA Packages only for imx-rt :-)
    Quote Originally Posted by chileflora View Post
    Strange, in their manual there is also the LQFP Pinout...(https://www.pjrc.com/teensy/K64P144M120SF5.pdf)
    That's not a imx.rt i was talking about.

  8. #33
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by chileflora View Post
    From you experience, how would Teensy 3.5 versus 3.2 rank in terms of temperature and time robustness (vibration and moisture are relatively minor issues)? and also if we go into comparisons, how would a 2560 board (specifically Robotdyn pro which I was using before) and a Pixhawk rank here?
    Truth is, PJRC spends most engineering time developing new features and software support, and also on improving manufacturing yield and production testing. I don't have solid answers for these sorts of questions, because it is simply not where we focus engineering effort.

    At this moment, I'm working on bringing up the optional external memory feature we'll have on Teensy 4.1, and pretty much all last week I worked on bringing up the ethernet port. Between more USB types, including many-channel USB audio, a long list of audio library features, Python support, more USB host device drivers, and the amazing 1170 chip we'll get later this year.... well, I think you can see how much engineering work is being done (or at least attempted) by such a small company. We just don't have the focus or time to pour into things like extended temperature testing, which isn't really a major feature for Teensy.

    But in terms of other boards to consider, maybe look at Arduino's upcoming Portenta H7. It does use BGA chips, but Arduino has specifically mentioned how Portenta H7 has been designed for extended temperature usage in demanding industrial applications. I believe it offers a large number of I/O signals via a pair of high density connectors, in addition to the usual breadboard-friendly pins on the outside edge. If you need a lot of signals and extended temperature, maybe Portenta H7 can fill those needs better than Teensy?

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