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  1. C

    Teensy 4 Multi-pin TDM audio, Multi-channel USB, and variable sample rates

    Hi all I just submitted the following pull requests and wanted to get your take on them. https://github.com/PaulStoffregen/cores/pull/732 https://github.com/PaulStoffregen/Audio/pull/470 These two pull requests do the following: Allows for the TDM interface to use all 4 pins for either play...
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    HOWTO develop teensy framework in structured manner?

    Yup, that's pretty much what I ended up doing. Thanks, -C
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    HOWTO develop teensy framework in structured manner?

    I should have known you'd have an easy way to do it my friend! Does it work for cores as well? I suppose I could test it myself ;-)
  4. C

    HOWTO develop teensy framework in structured manner?

    Ah! Thanks for the reply. Sounds about as ad-hoc as what I was doing :-) I just found a method with platformio that actually works reasonably well: I do a clone like you did of the libraries, but put them into <mylibdir>/framework-teensyduino, so it includes framework-teensyduino/cores...
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    HOWTO develop teensy framework in structured manner?

    Hi All, I'm editing and updating code in the teensy framework, fixing buts, etc. Is there a preferred way to check out all the teensy repos from github, and edit them, rather than use the auto-downloaded code from the Arduino/platformio tools? My current method is using platformio command...
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    input_tdm bug: every other sample on odd channels is swapped

    Just realized, this is also a problem with tdm2. updated the pull request to include both tdm, and tdm2. https://github.com/PaulStoffregen/Audio/pull/428 -Caleb
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    input_tdm bug: every other sample on odd channels is swapped

    Hi there, I found a bug in the Teensy audio library, TDM, where every other sample on odd channels is swapped. That is, on channels 1, 3, 5, 7, 9, 11, 13, 15, the odd and even samples are swapped. I've created a pull-request here: <see below> with the requisite fix. Thanks, -Caleb
  8. C

    48kHz 8i80 USB Audio

    I'm working on this right now too :-) Though making it N channels for rx and M channels for tx. There's no reason to stop at 4. I'm refactoring the code to get rid of all references to 'left' and 'right', but making everything arrays of channels. We'll see how it goes :-) If anybody's...
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    Patches for running USB audio at other audio rates (8000, 16000, 32000, 48000, etc)

    Hi All, I've created a patch that allows USB audio rate to track the AUDIO_SAMPLE_RATE. This lets you defined AUDIO_SAMPLE_RATE at compile time, and stream USB audio from the computer a rate matching AUDIO_SAMPLE_RATE. I have done some cursory tests at 8000, 16000, 32000, 48000, and they...
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    Has the Teensy 4.x been tested with USB Hubs? (ERR050101)

    Hi there, I've been developing with the MIMXRT10xx, and can say with confidence that ERR050101 is an egregious bug in the chip. It's a problem specifically with the 1062 rev A silicon, and ALL 105x chips, and many others in the family. The 1011 and 1015, and 1062B I think are the only ones...
  11. C

    Setting flash security byte

    Hi there, Just to make things even easier, I just submitted a pull request here that makes it a compiler #define. https://github.com/PaulStoffregen/cores/pull/199 Also, by editing the boards.txt file, as specified in the comment to this pull request, you get a nice UI switch between secure...
  12. C

    Teensy Audio: MCLK is not stable

    Here's a modified version that can simulate different fixed point numbers (badly). from numpy import * from pylab import * fs = 44100.0 frequency = 12001 # some oddball frequency not a perfect multiple of fs. state = complex(1.0 + 1j*0) # compute this many samples n = 1000000 #...
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    Teensy Audio: MCLK is not stable

    Yes. I just typed that pseduo-code off the top of my head. :-) Well, in c++, you can make a complex number type that does the complex multiply. But, a complex multiply goes like this: to multiply c = a * b where a, b and c are complex numbers goes like this: Break the a and b into their...
  14. C

    Teensy Audio: MCLK is not stable

    Oops, posted too soon by accident: By the way, did you consider generating a sine wave with a phasor? If you store state as a complex number, then you can simply calculate the next sample my multiplying the state with a phasor. Basically, it goes like this: typedef struct { int32_t...
  15. C

    Teensy Audio: MCLK is not stable

    By the way, did you consider generating a sine wave with a phasor?
  16. C

    Teensy Audio: MCLK is not stable

    I checked your sine table, and at exact multiples of the fs/256 frequency, it was quite accurate. But I checked with the hires just to see, and the results are virtually identical. Very very minor differences: This shows the 96MHz with the original sine, vs 96MHz with the hires sine: And...
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    Teensy Audio: MCLK is not stable

    Okay, I measured the IMD using the built-in sine generators (so I didn't have to use the ADCs -- which are very noisy for my setup... will be a subject of another post), and the results say... the differences are measurable, but only barely. First the sketch I used to generate a dual-tone...
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    Audio tool generation bug: renaming nodes

    FYI, I just created a little patch that seems to fix the problem for me. I have not extensively tested it, but it works for my purposes. https://github.com/PaulStoffregen/Audio/pull/182 -Caleb
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    Teensy Audio: MCLK is not stable

    Duty cycle isn't critical (sort of). If it's 66% high/33% low, that's fine as long as you meet the timing requirements of the chip. It's the timing of the successive rising (or falling) edges that matter. However, I don't have any insight into the STGL5000. If it uses rising edges to clock...
  20. C

    Teensy Audio: MCLK is not stable

    No, really, the codec sees MCLK independently of LRCLK. It's MCLK that drives the delta sigma converters, utterly independently of LRCLK. It's MCLK alone that matters here. LRCLK and BCLK can jitter wildly all over the place, but MCLK should be stable. LRCLK and BCLK must only be correct on...
  21. C

    Teensy Audio: MCLK is not stable

    Well, just look at the trace I posted. Count the first rising edge in the center of the screen. The next rising edge is at one of 2 locations, either 90ns or 82ns later. https://forum.pjrc.com/attachment.php?attachmentid=7242&d=1464279513 Edit: I just understood that your question is not...
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    Teensy Audio: MCLK is not stable

    Hello, I love the Teensy audio board (just got it yesterday). However, the audio clock MCLK is not stable, which is the cause of some icky distortion. In the attached image, you can see the MCLK signal (pin 11), and clearly it has bi-modal duration with periods of about 90 ns and...
  23. C

    Audio tool generation bug: renaming nodes

    Hi All, Fantasic job on the Teensy and the audio library! This makes my little project super easy! I just had a report of a bug on the audio tool code generator when I rename the nodes. Here's the image of the code generator: And the generated code is: #include <Audio.h> #include...
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    Website bug: bugzlilla link forbidden

    Hi Paul, Just reporting a bug in the website: The home page has a link to buzilla to http://pjrc.com/bugzilla/. But if I click on it, it I get a big 'Forbidden' message. Not sure if this is on purpose or not, but I just thought I'd report it. Thanks, -Caleb
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