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Thread: I2S pins - Teensy 3.6

  1. #1

    I2S pins - Teensy 3.6

    Hello,

    I try to figure

    - the i/o pins used on the Teensy 3.6 for I2S so I can plug my own chip to it

    - do I need to modify input_i2s.cpp, considering that the chips I looked at don't have the same I2S pins

    chips :

    PCM1802 pins : LRCK FSYNC DOUT BCK SCKI (this one supposed to match LRCK, but it's not really clear in the datasheet)

    CS5343 pins : LRCK MCLK SDOUT SCLK

    I am bit confused, since PCM1802 has an additional pin, and the names barely match

    any help, greatly appreciated

    thanks

  2. #2
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    Quote Originally Posted by phil123456 View Post
    Hello,

    I try to figure

    - the i/o pins used on the Teensy 3.6 for I2S so I can plug my own chip to it

    - do I need to modify input_i2s.cpp, considering that the chips I looked at don't have the same I2S pins

    chips :

    PCM1802 pins : LRCK FSYNC DOUT BCK SCKI (this one supposed to match LRCK, but it's not really clear in the datasheet)

    CS5343 pins : LRCK MCLK SDOUT SCLK

    I am bit confused, since PCM1802 has an additional pin, and the names barely match

    any help, greatly appreciated

    thanks
    From Reference (figure23 and 25) you can see that for PCM1802 FSYNC controls the start of data transmission (data are only send when FSYNC is high) Consider it some sort of chip-select. You can use any digital pin for that

    so my suggestion is
    Teensy.. | CS5343 |PCM1802
    MCLK... | MCLK.... | SCKI
    BCLK.... | SCKL.... | BCK
    LRCLK.. | LRCK..... | LRCK
    DIN..... | SDOUT... | DOUT
    Pinx..... | ----- .. | FSYNC

  3. #3
    Senior Member+ MichaelMeissner's Avatar
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    And note, that in the Teensy 3.2, 3.5, and 3.6, the I2S pins overlap with the SPI pins. This means if you want to hook up a display using SPI, on the 3.x systems, you have to use the alternate SPI pins. Unfortunately, in the 3.x pinouts, the I2S pins were not listed in the various pinout cards.

    On the Teensy 4.0, the I2S pins are completely different and do not overlap with the SPI pins.

    If you go to the audio shield product page, it lists the I2S pins for both the 3.x Teensies and the 4.0 Teensy:


    For completeness sake, the Teensy 3.1 has the same pinout as the Teensy 3.2.

    I don't believe the Teensy LC supports I2S. Even if it did, the M0 processor inside of the Teensy LC is not compatible with a lot of the audio library, so don't even consider using the LC for I2S work.

    Similarly, I don't believe the original Teensy 3.0 supported I2S either.

  4. #4
    Ok, I found it indeed

    MCLK 11 Audio Master Clock, 11.29 MHz
    BCLK 9 Audio Bit Clock, 1.41 or 2.82 MHz
    LRCLK 23 Audio Left/Right Clock, 44.1 kHz
    DIN 22 Audio Data from Teensy to Audio Shield
    DOUT 13 Audio Data from Audio Shield to Teensy

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