I just bought an ESP8266 ESP-07 V1.0 Serial Wifi Transceiver. Similiar to this: https://www.ebay.com/itm/ESP8266-Serial-Wifi-Transceiver-Module-for-Arduino-ESP-07-V1-0-New-/331868488091

I have connect the RX and TX pins to the RX and TX pin of the Arduino (RX to TX and TX to RX), VCC is connected to 3.3V and GND is connected to Arduino ground. I have used the following code and writing commands to the module using the serial monitor:

#include <SoftwareSerial.h>

int RX_PIN = 3;
int TX_PIN = 4;

SoftwareSerial mySerial(RX_PIN, TX_PIN); // RX, TX

void setup()

    while (!Serial){

    while (!mySerial){
void loop()
    // listen for communication from the ESP8266 and then write it to the serial monitor
    if ( mySerial.available() )   {  Serial.write( mySerial.read() );  }

    // listen for user input and send it to the ESP8266
    if ( Serial.available() )       {  mySerial.write( Serial.read() );  }

Whatever I type (for example AT+GMR) in the serial monitor at 9600 baud I don't get any response. What could be the reason? Both NL and CR is added to the command.

When pressing reset on the ESP-module I get this in the Serial monitoring:

enter image description here

Thanks for any help!

  • pin 1 is TX of hardware Serial. and the esp8266 should be on SoftwareSerial RX/TX pins, not on RX/TX labeled pins
    – Juraj
    Commented Oct 3, 2019 at 7:49
  • @Juraj Thanks for your reply. I have now updated the code. But still no luck :-/
    – Araw
    Commented Oct 3, 2019 at 10:11
  • and the wiring?
    – Juraj
    Commented Oct 3, 2019 at 10:58
  • @Juraj Arduino RX (pin 3) => ESP TX, Arduino TX (pin 4) => ESP RX, Arduino 3.3V => ESP VCC, Arduino GND => ESP GND
    – Araw
    Commented Oct 3, 2019 at 11:12
  • 1
    set the baud rates to 74800 to see the boot log
    – Juraj
    Commented Oct 3, 2019 at 15:49

1 Answer 1


The esp8266 is without AT firmware. Even with SoftwareSerial at 115200 baud you should see "ready" from AT firmware and get some response to AT commands.

This esp8266 module adapter is simple to flash. It makes the 5 V to 3.3 V conversion for power and RX pin and has a program switch (io 0) and a reset button to put the esp8266 into flashing mode.

Use an USB-to-TTL-Serial adapter or an Arduino with USB chip to connect the adapter to PC. Then switch to "program" and reset it and it will be in flashing mode.

You can download the AT firmware here. I recommend ESP8266 NonOS AT Bin V1.7.1. Don't try 2.0, it is very different (ESP32 AT firmware build for esp8266).

To flash it, use esptool

The command to flash the AT firmware binaries to any module with at least 1 MB flash memory is:

esptool.py write_flash --flash_size 2MB-c1 0x0 boot_v1.7.bin 0x01000 at/1024+1024/user1.2048.new.5.bin 0x1fb000 blank.bin 0x1fc000 esp_init_data_default_v08.bin 0xfe000 blank.bin 0x1fe000 blank.bin

don't wonder about the 2MB-c1 setting and don't change it. The AT binaries are build for 2MB-c1 partitioning. On 1 MB flash it will not support AT firmware OTA update.

If you want to use the Espressif Flash Download Tool, use the same settings as on esptool command line.

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