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I have exactly this model of esp8266: enter image description here I removed Atmega328p IC from Arduino, and powered Arduino with USB cable. After all, I made this connection combinations:

1)
ESP Tx > Arudino Tx
ESP Rx > Arduino Rx
ESP 3.3v > Arduino 3v3
ESP Dh_cp > Arduino 3v3
ESP Gnd > Arduino Gnd
ESP GPIO0 > GND

2)
ESP Tx > Arudino Rx
ESP Rx > Arduino Tx
ESP 3.3v > Arduino 3v3
ESP Dh_cp > Arduino 3v3
ESP Gnd > Arduino Gnd
ESP GPIO0 > GND

3)
ESP Tx > Arudino Tx
ESP Rx > Arduino Rx
ESP 3.3v > Arduino 3v3
ESP Dh_cp > Arduino 3v3
ESP Gnd > Arduino Gnd

4)
ESP Tx > Arudino Rx
ESP Rx > Arduino Tx
ESP 3.3v > Arduino 3v3
ESP Dh_cp > Arduino 3v3
ESP Gnd > Arduino Gnd

I checked both 9600, and 115200 baud, but on any of them I did not get a reply to the AT command. Have I done something wrong? I get weird characters when disconnecting ESP's GND wire, so some communication exists.

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  • 1
    with io 0 LOW the esp8266 starts in flashing mode. add a pull-up resistor for io 0. the TX pin of nano is wired to RX pin of the USB chip. so to have RX to TX wire TX to TX :-)
    – Juraj
    Nov 2, 2020 at 11:09
  • how did you remove the ATmega from Nano?
    – Juraj
    Nov 2, 2020 at 11:15

1 Answer 1

1

If it is not a genuine Arduino (Chinese clone probably) and it has the CH340 USB to Serial converter chip, then it will not work as the digital Signal on TX does not get pulled to ground when transmitting a digital LOW, (if that's the right way to say it). There seem to be resistors on the board that cause this effect, or something. I do not guarantee that this is your problem but it's highly likely.

Use an FTDI USB to Serial board or similar and you might have better results.

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