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      DrM replied to the thread Teensy 3.2 End Of Life.
      @PaulStoffregen First, aside, Paul have you tried that ADC we talked about somet time ago? That one has a mux and can share one opamp for all of the channels. I will post or send you the design files if anyone is interested, with the...
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      • SAR_opamp_RC20x1_currents_cropped.jpg
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      A new repos, or rather an old repo with new content is posted to github. https://github.com/drmcnelson/Arduino_Timing There you will find some measurements for timing for digital write, read, toggle, SPI transfers, interrupt latency and so...
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      DrM replied to the thread Send data from Teensy to Python.
      Two comments, one is a correction to my previous. If you can serialize your exchanges, then that is a third approach. Bottom line, it is about getting the data from he driver before the internal buffer in the driver runs out of room. Re the...
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      DrM replied to the thread Send data from Teensy to Python.
      I regularly send about 4000 values, in either binary using write or formatted using print. You can see my code for one example of this at: https://github.com/drmcnelson/Linear-CCD-with-LTSpice-KiCAD-Firmware-and-Python-Library There is a...
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      I know the spec is thru hole, but SMT is really not that hard. Reflow ovens are on ebay for even $200, get some nice solder paste and tweezers and a magnifier (wearable is nice), and stick with doable size parts, at first. It really is...
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      Similar idea, the 74LVC1T45 are nice. You have voltage on each side, and a direction pin. I run VD to the interface connector so the other end can tell me what power it is using.
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      @MarkT, yes I appreciate the challenge. That is why there are researchers working on the kT/C noise challenge. Maybe some major breakthrough in dieliectrics will give us a smaller 10pf some day, or some other way to store charge linear in V...
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      SPICE models for the Teensy4 ADC Input @MarkT - this addresses the points you raised, I hope. The last figure I think might explain why that sampling cap is only 2pf, besides that it is only 12 bits. The Teensy3.2 had 10pf for 16 bit mode...
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      • Teens4SAR_slow_fast_thermistor.png
      • Teens4SAR_slow_slow_thermistor.png
      • Teens4SAR_bufferd_fast_fast_thermistor.png
      • Teens4SAR_bufferd_slow_fast_thermistor.png
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      @MarkT - i see the confusion, it is not about a slow or fast changing signal, it is about the sampling window of the SAR. You could say the switch makes it a fast changing signal, so-to-speak. Notice that the spice model has a DC level on the...
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      @MarkT, could you show how that works? To check, you said 100nf from input to ground, right? Like this??? It seems like 100nf means you now have a time constant of about 1msec. That would mean you now need order 10 milliseconds before...
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      @Paul hi, hopefully this is helpful. I wasn't sure which to which forum it should be posted. Suggestions?
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      There are a lot of posts on this and many other forums that go something like "Why am I getting incorrect readings or weird behaviors from the analog input?" And there are lots of responses that go something like, just use this code. If that...
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      The problem, not mentioned in that tutorial, is that the analog input is a SAR type ADC. I recall the sampling capacitor for the Teensy 4. is something like 30 or 40 pf. They almost always are in that range because of the famous kT/C noise...
      • SAR_thermistor10K.png
      • SAR_opamp_R100_cropped.jpg
      • SAR_opamp_RC20x1_cropped.jpg
      • SAR_opamp_RC20x1_currents_cropped.jpg
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      DrM replied to the thread Multiple Analog Inputs.
      How are you interfacing the microphones to the analog input pins?
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