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Thread: Serial5 on teensy 4.0

  1. #1
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    Serial5 on teensy 4.0

    Hi all,
    Just a quick verification that the pins are correct on the card for Serial5 on the teensy 4.0 (pins 20 and 21 for TX and RX, respectively). I'm having some issues communication via Serial5 (RX in particular) and trying to determine if it's my code (most likely), my PCB design (quite possibly), or something else. I looked at core_pins.h and seems to be correct:
    #define CORE_RXD4_PIN 21
    #define CORE_TXD4_PIN 20
    (assuming RXD4/TXD4 = Serial5).
    Would love another set of eyeballs on this just to make sure.

    Thank you!
    David

  2. #2
    Senior Member+ defragster's Avatar
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    Yes, that matches the PJRC Card for T_4.0: pins 20 and 21 for TX and RX, respectively.

    Only problem might be using AUDIO board or something else setting up and changing those pins with pinMode() or other.

  3. #3
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    Thank you for checking. I think I found my issue: the watchdog library I'm using (Watchdog_t4.h) and serial5 RX use the same pin! Woohoo! Except now I need to figure out why the watchdog needs that pin I swear I've gone through the code a hundred times...now it just jumps out at me.

    Thanks again for the nudge in the right direction!
    David

  4. #4
    Senior Member+ defragster's Avatar
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    Cool - glad that rang a bell. Not sure what the watchdog code uses that pin for without a closer look at the code.

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