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Thread: Teensy 4 ADC and I2S sample rates

  1. #1
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    Teensy 4 ADC and I2S sample rates

    I'm looking for information on the maximum sample rates for I2S and the 12-bit ADC on the Teensy 4. I saw something in the iMX RT1060 data sheet about the bit clock timing for the I2S as 40ns (25 MHz) but I'm not sure if this is the same for the 1062 or if there are other limitations. A quick glance at the ADC specs and I didn't see the rates there. I assume it's a SAR ADC so the rate will be determined by the accuracy.

    I'm looking to sample some relatively high frequency data (1's to 10's of MHz) and I'm deciding if I need to use an external ADC and if so, what bus to use for the transfer. I2S is a preferred option as it should easily allow design of DSP processing using the existing audio library.

  2. #2
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    i have used Bumblers' V0 adc library (search in technical for "adc") to get 12 bit conversions in about 0.8 us
    going 10 or 8 bits speeds it up some but not a lot.
    since that is your low end i think you need an external adc.

    to get that 0.8us you have to use hardware averaging of 0 and that makes for some fairly noisy data.
    data starts to look clean at average of 4 but then your sample time goes to about 1.5 us

    i have not used the I2S or I2C

  3. #3
    Senior Member+ defragster's Avatar
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    Quote Originally Posted by retrev View Post

    I saw something in the iMX RT1060 data sheet about the bit clock timing for the I2S as 40ns (25 MHz) but I'm not sure if this is the same for the 1062
    ...
    The 1062 is the 1060 in the shipping REV #2 version.

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