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  1. Thread: GND vs AGND

    by BJB
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    2,684

    Have never been a big fan of these current...

    Have never been a big fan of these current sensors, but they are functional for simple stuff.

    The 'best' design practice would probably be to leave the fault pin open and connect the 'ground'...
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    Concur with XFer and brtaylor. Based on...

    Concur with XFer and brtaylor.

    Based on several HALT series done with Teensy 3.2s, do not recommend use in industrial control products where internal ambient is under -20C.

    As 'industrial'...
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    Am not certain that a supply (bypass) cap will do...

    Am not certain that a supply (bypass) cap will do much to arrest voltage or current output surges, and is intended to provide short-term pulsed-current demands. That is, the bypass cap is intended to...
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    May I suggest https://www.eevblog.com/forum/ ?

    May I suggest https://www.eevblog.com/forum/ ?
  5. Yet another 'it depends'. Have two model...

    Yet another 'it depends'.

    Have two model series for my side business.

    For simple low-end stuff (atmel 328s, TI 430s, etc), have never used any of the canned proto boards. But this is to mostly...
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    242

    Simple (electrical) varnish coating will be ok...

    Simple (electrical) varnish coating will be ok for higher %RH environment where absolutely nothing comes out of solution; that is, non-condensing. Otherwise the only two solutions (pun unintentional)...
  7. Am not certain if the A5250 reference makes your...

    Am not certain if the A5250 reference makes your point. It states the 'obvious'. Gain and offset errors are the (relatively) easy stuff. INL, DNL, reference stability, Z-mismatch, digital noise and...
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    Caveat -> NOT a lawyer. The meaning of OS/OH...

    Caveat -> NOT a lawyer.

    The meaning of OS/OH has been litigated and legislated differently throughout the world. The EU courts treats OS licenses differently than the U.S. and Canada.

    Unless...
  9. Thread: FCC Certification

    by BJB
    Replies
    1
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    466

    1. starts at 9kHz. - exemptions for...

    1. starts at 9kHz.
    - exemptions for unintentional radiators are found in 47 CFR 15.103.
    - certification not necessarily required unless connected to mains.
    - did a subpart B test series for a...
  10. Replies
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    Apologize for the OT diversion. Have been...

    Apologize for the OT diversion.

    Have been supporting LabView stuff at various sites for over 25 years; and did one or more (will never admit in public) production ATE systems for the factory floor...
  11. Replies
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    We pause this conversation for a comment from the...

    We pause this conversation for a comment from the resident crank.

    USB 3 energy and current levels are problematic. And the new IEC62368-3 is designed to rein in some the the weird stuff now found...
  12. Thread: Teensy 4 RTOS

    by BJB
    Replies
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    3,055

    YASQ (yet another stupid question) What are...

    YASQ (yet another stupid question)

    What are you good people doing that would require more than a scheduler/state machine?
  13. Thread: Compliance issue

    by BJB
    Replies
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    714

    I do not speak for PJRC, my employer, or the...

    I do not speak for PJRC, my employer, or the Klingon Empire.

    There is no such official animal as a RoHS or REACH 'compliance certificate'. No requirement unless the equipment is within scope of a...
  14. What are "acoustic counter waves" ? Noise...

    What are "acoustic counter waves" ? Noise cancellation?
  15. Replies
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    Will assume for various technical and legal...

    Will assume for various technical and legal reasons, PJRC has not included specific tabulation of environmental specifications. And, as this is a 'systems' question, will have to be a DIY thing.
    ...
  16. Typically, NRTLs will not, and cannot, provide...

    Typically, NRTLs will not, and cannot, provide design services, other than to review a design proposal or do a gap analysis on an existing design. If your knowledge of a standard exceeds that of an...
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    Agree. Probably not gonna find much robust and...

    Agree. Probably not gonna find much robust and capable analog stuff buried in a powerful digital glob. So if we need this level of GPIO and processing power, one would probably goto external stuff...
  18. This is not the forum for IS design. Your team...

    This is not the forum for IS design. Your team needs to invest in an initial study of the software and hardware and environmental standards that are scoped for your category and class.

    One of...
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    Today's conversation with the NRTL client test...

    Today's conversation with the NRTL client test data program auditor.

    NRTL guy - do you have any code on github?
    me - nope, all on a local svn box
    NRTL guy - show me
    me - looky here [tappity...
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    Dunno, could be considered the same stuff as...

    Dunno, could be considered the same stuff as using 365... says the crazy old geezer that uses subversion.

    Do not be surprised if 'they' decide to force a mickeysoft login, as has happened in the...
  21. Replies
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    We are about exceed the processing power of a rpi...

    We are about exceed the processing power of a rpi or pi-zero without the madness of a huge OS, and we need to stay calm in our anticipation? An entirely unreasonable request.
  22. Replies
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    Dunno, perhaps I am too stupid to understand what...

    Dunno, perhaps I am too stupid to understand what is being said. Am certain that most of our august group would like to help this guy, but simply cannot parse the question or issues. Have had similar...
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    Dunno. Is spam crassly commercial, or just a...

    Dunno. Is spam crassly commercial, or just a babble post with no useful information or no relevant question ?

    It is, in my opinion, the latter.
  24. Replies
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    Contamination, per se, was not the problem. We...

    Contamination, per se, was not the problem. We had a batch of 29 sensors with deteriorating tolerances after a few months of several cycles per day (20 to 80%RH, -20 to 40C), of working 24/7. We...
  25. Thread: GND vs AGND

    by BJB
    Replies
    15
    Views
    2,684

    Hath spake "Your end-use application should never...

    Hath spake "Your end-use application should never allow these two returns to touch.."

    Now read that again. Did not say to "never" connect gnd and agnd. Said to not connect in the END-USE...
  26. Thread: GND vs AGND

    by BJB
    Replies
    15
    Views
    2,684

    Discussed in numerous threads on the PJRC forum,...

    Discussed in numerous threads on the PJRC forum, and in the microcontroller reference tome.

    In a nutshell, 'GND' is for digital returns (I2C, I2S, SPI, GPIO, etc), and 'AGND' is the zero...
  27. Replies
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    https://forum.pjrc.com/threads/29108-Teensy-operat...

    https://forum.pjrc.com/threads/29108-Teensy-operating-temperature?p=77355#post77355

    Have subsequently did a partial regression on a unit with a Teensy 3.5, where decreased margins were indicated....
  28. Thread: lo noise stuff

    by BJB
    Replies
    3
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    424

    Have done things much more stupid than this, so...

    Have done things much more stupid than this, so verified the ardy IDE config for 24MHz on the tech's windoze box and is correct. Mine typically uses SCons on Linux, so very little mouse clicking or...
  29. Thread: lo noise stuff

    by BJB
    Replies
    3
    Views
    424

    lo noise stuff

    Am doing some lo-noise stuff (per CISPR22/32 class B limits). For various reasons, not all related to noise, cannot exceed a 24MHz clock.

    Have tested various ATtiny and other AVRs, and some M0 and...
  30. Replies
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    https://forum.pjrc.com/threads/47977-High-sampling...

    https://forum.pjrc.com/threads/47977-High-sampling-rate-measurement-for-weak-electrish-fish?highlight=adc+rate
    ...
  31. Thread: state machines

    by BJB
    Replies
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    827

    Vague hand-waving follows. State machines...

    Vague hand-waving follows.

    State machines should not be a problem for 'moderately' sized code. Have done some state machines with T3.1s and T3.2s, but do not directly use the arduino system. That...
  32. Replies
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    "I also noticed the teensy board was very hot...

    "I also noticed the teensy board was very hot with only 5 volts to Vin"

    Nope, do not want to touch these units.

    And does anyone want my four T3.2s that had 1200Vdc on the USB port? Only...
  33. SMPS and linear source are contradictory terms...

    SMPS and linear source are contradictory terms where "no ripple" is your reference specification.

    There are some things that you can do to approach a low noise design, but you will not "reduce the...
  34. Replies
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    Condensation not likely, as same problem with...

    Condensation not likely, as same problem with sensors in all of my employer's environmental chambers at both factory and engineering sites. And my code running the chambers reads a parametric look...
  35. Replies
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    MOVs can be dangerous. They will oft explode...

    MOVs can be dangerous. They will oft explode while 'arresting' the surge and start a fire. Study annex Q of IEC/UL60950-1, IEEE C2-2012, and UL1449.

    Product safety does not care about...
  36. Replies
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    The ADC probably not really 18b unless the op amp...

    The ADC probably not really 18b unless the op amp and the reference choices are re-considered.

    To get at least 16b of useful data, my stuff typically uses a 24b ADC and low-noise/lo-Vos/low-Ib op...
  37. Interesting. Did a much less complete version of...

    Interesting. Did a much less complete version of Firmata-like stuff last year after the factory techs insisted on blowing up $$$ per month of test equipment. Built about 10 of these where the USB...
  38. Replies
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    Question - been using models BME280 and BMP280...

    Question - been using models BME280 and BMP280 for approximately 20 months in some environmental chambers. First batch lasted about 10 to 11 months, and second and third batches ok no more than 6...
  39. Replies
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    Have looked at many a M0/3/4 board. Many have...

    Have looked at many a M0/3/4 board. Many have quality problems from marginal manufacturing processes or marginal quality passive components, or may simply not be a reliably sourced widget as they are...
  40. Replies
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    Actually, it would be "get off of my dirt". My...

    Actually, it would be "get off of my dirt". My 'museum' drawers have 8080s (curse the 2-phase clock and sequencing of the three power rails) and Z80s from S100 projects. 8051/6502 assembler were...
  41. Replies
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    Same here. Developing with a T3.5 for a...

    Same here. Developing with a T3.5 for a calibration bench, and out of I/O, but much flash remaining. Will probably go with two or three T3.2s.



    External memory = noise. So would do serious...
  42. Replies
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    If pin config changed, would hope that more...

    If pin config changed, would hope that more consideration given for noise. Aref and analog ground need a little more protection from that evil digital stuff. 600MHz is an order of magnitude greater...
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    Was also looking at this and being confused, but...

    Was also looking at this and being confused, but as am very ignorant of windows as a dev platform, did not expect that old stuff would be installed from a recent (26June) download of this stuff. In...
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    Unable to compile under windoze

    Bad dreams do come true - Arduino IDE + windoze, so hat in hand time...

    Setting up a high school lab for the summer embedded seminar. Teensyduino and libs installed and running ok on the Linux...
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    https://forum.pjrc.com/threads/41857-Options-for-b...

    https://forum.pjrc.com/threads/41857-Options-for-bare-metal-development

    PJRC is working on using more recent GCC versions; and is working on ethernet stuff for the T3.6.

    STL has been in GCC for...
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    For almost 15 years, some of the direction for...

    For almost 15 years, some of the direction for ISO C++ has been from the IEC Technical Reports. One of the original attempts to make memory more safe was from the Boost libs - the 'enhanced member...
  47. Replies
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    Gate the output using a timer, or discretely...

    Gate the output using a timer, or discretely control the signal gate with a dig i/o pin.
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    Back when we were doing lots of widget...

    Back when we were doing lots of widget development on T3.1s then 3.2s, built a simple 'loop-back' board that had headers for directly-mounted teensy, or could be pressed onto the test header of our...
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    My experience probably not relevant because my...

    My experience probably not relevant because my widget has no directly "exposed pins". Would suspect that the MM would be relevant for direct Teensy contact, and the HBM data would be applicable for...
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    [Foghorn Leghorn voice] "That is a joke, son..."...

    [Foghorn Leghorn voice] "That is a joke, son..."

    Actually the 1500V was from where an electrician touched a PV string sense lead to my box with the cover off. For ESD immunity verification, did...
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