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    Some info here: ...

    Some info here:

    http://ww1.microchip.com/downloads/en/appnotes/an-120%20capacitive%20coupling%20for%20ethernet%20transceiver.pdf
  2. You could print out the String just after you...

    You could print out the String just after you read it in (before parsing). Copy the output into https://jsonlint.com/ to check it. Also note that the library does have a nesting limit.
  3. You should post your code. You can read > 150...

    You should post your code. You can read > 150 bytes into a temporary string and pass this to deserializeJson().
  4. Thread: issue with gps

    by jonr
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    > Adafruit_GPS _uGPS(&GPSSerial); This line in...

    > Adafruit_GPS _uGPS(&GPSSerial);

    This line in your constructor creates another local only shadow _uGPS - which isn't what you want.
  5. I find 25 to 60 cycles with a rated field life of...

    I find 25 to 60 cycles with a rated field life of 3 to 5 years. But specific versions could be different.
  6. Sounds to me like you want "input capture", where...

    Sounds to me like you want "input capture", where the hardware records the time when pins change.
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    Hopefully someday we will have RTP audio over...

    Hopefully someday we will have RTP audio over ethernet/IP/UDP as a standard I/O device in the teensy audio library. This would be a building block towards eventual support of AES67 (which uses...
  8. Thread: debugging.......

    by jonr
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    You can add lots of timing calls before and after...

    You can add lots of timing calls before and after subroutines or sections of code. Eventually you will know where it's spending so much time.
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    It's a shame that so many groups are duplicating...

    It's a shame that so many groups are duplicating effort. There needs to be more consolidation - so efforts are combined. ArduinoCore-mbed (Arduino on top of Mbed) might be a good API option.
    ...
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    It's been awhile, so you are providing some good...

    It's been awhile, so you are providing some good practice.

    Looks like air films are normally specified as conductance "C" in W/m^2 K, not conductivity "k" (as I wrote above). So it doesn't...
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    I agree, a mostly separate issue. But on the...

    I agree, a mostly separate issue. But on the other hand, I'm guessing that the concern with such a change is testing across lots of platforms and rates - which your code also needs. So convenient...
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    > the low thermal resistance of the aluminum box...

    > the low thermal resistance of the aluminum box

    Agreed, but the conductivity of the air films is critical to the correct calculation of conduction from a free standing box. Maybe k=4, about...
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    Here is some support for only two states in the...

    Here is some support for only two states in the feedback (see the response from the NXP employee):

    https://community.nxp.com/t5/Kinetis-Microcontrollers/USB-audio-sync/m-p/191408
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    I use pulseaudio with Linux. The windup issue...

    I use pulseaudio with Linux. The windup issue has something to do with unused audio devices being put to sleep while not in use. Possibly the PC sends USB packets that are empty? So "f" is true...
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    Agreed, black in areas not in the sun would...

    Agreed, black in areas not in the sun would radiate about 5% better than white. Shiny aluminum has poor radiant performance.
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    Now would be a good time to fix the poor control...

    Now would be a good time to fix the poor control algorithm for samples requested from the PC. Specifically:

    > if (f) feedback_accumulator += 3500;

    This suffers from integral windup which...
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    > depending on the thermal properties of the box,...

    > depending on the thermal properties of the box, if no heat is removed from the box, a sealed box will keep all heat inside

    But a perfectly insulated box doesn't exist. And since the box is...
  18. IMO, splitting or combining 25 normal sized...

    IMO, splitting or combining 25 normal sized ethernet frames at 17 Mbits/sec will be a minimal load on a teensy 4. If you see a big impact, it's not coded right.

    More info on jumbo frames here:...
  19. I'm curious - why do you care about jumbo frames...

    I'm curious - why do you care about jumbo frames vs just sending smaller ones and combining them? Only substantial drawback I know of is when there is packet loss.

    I wouldn't count on other...
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    A heatsink stuck to the T4 processor will make it...

    A heatsink stuck to the T4 processor will make it run cooler, even inside of a sealed box.
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    I encourage you to actually measure the latency.

    I encourage you to actually measure the latency.
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    Some good info here: ...

    Some good info here:

    https://forum.pjrc.com/threads/60299-1-MSPS-on-a-T4-Is-this-possible?highlight=MegaSample+T4.0+ADC
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    Some good info here. In your case, pay...

    Some good info here. In your case, pay particular attention to the USB D+/D-.
    https://www.pjrc.com/store/ic_mkl02.html

    Vias in pads are a bad idea.
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    Don't do the short connection between A6 and B6 -...

    Don't do the short connection between A6 and B6 - go around the left side to get to B6.
  25. > push to the right and fill left? Shift to...

    > push to the right and fill left?

    Shift to the left and add new samples on the right (end of array with higher index).
  26. You could shift the array 128 samples then read...

    You could shift the array 128 samples then read in 128 new samples. This yields an partially updated result every 128 samples.
  27. But AFAIK, a delay before start and a delay...

    But AFAIK, a delay before start and a delay between start of FS and start of SCK aren't the same thing. Manually connecting FS late is an easy test.


    This delay can be implemented either by...
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    This T4.1 code reads 12 usable bits of input and...

    This T4.1 code reads 12 usable bits of input and synchronizes reads to an external clock signal:


    for (register unsigned i = 0; i < FFTSize; ++i) {
    register uint32_t data;

    do...
  29. I find: i.MX RT1060 remains in Longevity Program...

    I find: i.MX RT1060 remains in Longevity Program until May 2036.
  30. I believe that this post also reported success: ...

    I believe that this post also reported success:

    https://forum.pjrc.com/threads/52175-Audio-Recording-Logging-to-SD-card-gt-microSoundRecorder
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    Using RTP vs a proprietary format should just be...

    Using RTP vs a proprietary format should just be a matter of adding a 12 byte header to the packets. Then lots of standard tools work to play and analyse the streams. For example, "RTP Player" in...
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    +1 on using the standard RTP. It does have a...

    +1 on using the standard RTP. It does have a format for Linear PCM 16-bit Stereo audio.

    Reordering of packets doesn't happen on most networks.
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    You posted the following code: // below here...

    You posted the following code:


    // below here is critical - we are writing to flash that could contain active code
    __disable_irq();


    This doesn't appear in the flasher4.zip in #93. Also,...
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    You aren't using the version in #93. You...

    You aren't using the version in #93.

    You should switch to the latest version here (for Teensy 3 and 4):
    ...
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    Add a sequence number to the sent packets and...

    Add a sequence number to the sent packets and missing or out of orders packets will be easy to detect.
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    > if the audio clocks aren't aligned ... the...

    > if the audio clocks aren't aligned ... the audio samples will be stretched or squashed

    The typical behavior is that you eventually have a buffer under or over run. Resampling would...
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    I can tell you that...

    I can tell you that ":10010000D8041808000000000000000000000000F3" is a valid, 43 character line and passes all checks.
  38. Thread: Freezing Problem.

    by jonr
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    This should make it easy to determine what code...

    This should make it easy to determine what code is executing during the freeze period. A wild guess - the problem is triggered by a data race condition.

    https://github.com/ftrias/TeensyDebug
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    > You will have to insert a sample from time time...

    > You will have to insert a sample from time time - or you have to delete it.

    Or, much better, keep tweaking the audio clocks so they match. As systems like Dante prove, the match can be...
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    > an inherent problem with quantization Yes,...

    > an inherent problem with quantization

    Yes, but you can pre-shift the data to the left, reducing quantization error of the filtered result.
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    With proper design and buffering, I expect that a...

    With proper design and buffering, I expect that a Teensy 4.1 could handle lots of UDP audio streams.
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    Also think about how you will sync the audio...

    Also think about how you will sync the audio clocks between the sender and receiver. Without sync, you typically eventually get under/over runs.
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    I expect that getting an Arduino Due program to...

    I expect that getting an Arduino Due program to run on the T4 will be easy.
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    That line fails a length check. Perhaps the...

    That line fails a length check. Perhaps the checksum was dropped?
  45. Thread: Raspberry Pi Pico

    by jonr
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    > ADC has a design flaw How much of this can...

    > ADC has a design flaw

    How much of this can be fixed in software?



    > Arduino support based on mbed

    Might be something to consider for reducing the software work needed for future...
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    Apparently some installed-by-default interrupt...

    Apparently some installed-by-default interrupt service routine takes up to 2.5 usec. That's about 2000 ISR instructions, which seems like a lot for a T4 that appears to be idle. Any idea what is...
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    Agreed, but many other interrupts aren't...

    Agreed, but many other interrupts aren't synchronized like this. Good point about the advantage of hardware timing.

    With this software timed code (derived from defragster code) I get jitter of...
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    I'd collect 100K+samples to catch another ISR's...

    I'd collect 100K+samples to catch another ISR's effect on timing. Periods of disabled interrupts (common in teensy code) will also cause jitter.
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    Note that the T4 has a tweak-able audio clock...

    Note that the T4 has a tweak-able audio clock rate - so good use can be made of synchronization.

    A 1 pps single wire input to the teensy also works fine. Even a once per second byte from a USB...
  50. To be pedantic, the code in #15 is using a hash. ...

    To be pedantic, the code in #15 is using a hash. Below supposedly performs well for strings (not applicable here). murmur3 might be better for ints.

    I used to think it didn't much matter. Then...
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