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Thread: ESP8266 ESP12E Nodemcu Lua Lolin v3 and Teensy 3.2

  1. #1
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    ESP8266 ESP12E Nodemcu Lua Lolin v3 and Teensy 3.2

    Hi everyone.

    I'm getting headaches connecting my ESP to my Teensy 3.2.
    I'm confident my ESP is working as I managed to upload a sketch via usb and arduino IDE. The IotWebConf sketch works ok as I have my AP online.

    But I can't upload a sketch via my Teensy, nor can I acces the ESP via serial monitor (AT command returns nothing)
    I followed this instructables: https://www.instructables.com/id/ESP...ing-Connected/
    My esp board is this one: https://www.amazon.fr/gp/product/B07...?ie=UTF8&psc=1

    Here's my wiring:
    Esp VCC --> USB 5v
    Esp GND --> usb GND
    Esp RX with a voltage divider --> 220k --> Teensy RX1
    --> 100k --> GND
    Esp TX --> Teensy TX1
    Esp Gpio15 --> 10k --> GND
    Esp EN --> 10k --> Teensy 3v
    Esp RST --> 10k --> Teensy 3v

    I've tried to reverse RX and TX on the teensy with no success.
    An interesting fact is that I have the exact same problem with an other Esp (esp01).

    Might there be a problem with my teensy serial pins ?

  2. #2
    Senior Member vjmuzik's Avatar
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    For one Tx should go to Rx and vise versa, never Tx to Tx or Rx to Rx. You don’t need a voltage divider, both are 3.3v devices so that’s not needed, without knowing what sketch you’re running the issue could be either you haven’t routed the serial monitor to the hardware serial port or the resistor divider is causing the issue.

  3. #3
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    Here's the sketch I uploaded to my esp:
    https://github.com/prampec/IotWebCon...f01Minimal.ino

    I uploaded the bare minimum sketch on my teensy:
    https://www.arduino.cc/en/Tutorial/BareMinimum

    I'll try without the voltage divider.

    What do you mean by routing the serial monitor to the hardware serial port?

  4. #4
    Senior Member vjmuzik's Avatar
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    Looks like you actually have to flash the esp with the AT firmware, it doesn’t just work without it, here’s an instructable: https://www.instructables.com/id/ESP...g-AT-Firmware/

  5. #5
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    Actually, I don't really care for AT commands, it was just to test serial communication. Is the AT firmware needed for the teensy to use the esp?
    My goal is to send shell commands to my raspberry from my teensy over wifi. Will the AT firmware allow me to do so?
    I must admit I know nothing about esp firmwares.

  6. #6
    Senior Member vjmuzik's Avatar
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    I know nothing about it either, but you don’t truthfully need it to communicate between the two, you would just have to write your own serial commands that can tell your software on the esp what to do. I’m not sure how capable the builtin TCP/IP stack is on the esp you may have to write your own library for it to connect to a shell terminal on the raspberry, but I imagine it can be done.

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