ESP8266 Community Forum

- Mon Feb 29, 2016 6:22 pm #42127 Hello guys!
I'm just starting on ESP8266 world and I'm facing my firsts issues

I'm trying to connect the ESP to my Arduino Nano in order to be able to upload an sketch to the ESP through the Arduino.
After a research on the net I finally found a site where they explained how ESP8266 12E GPIO pins should be connected:

http://www.seeedstudio.com/wiki/images/ ... f_spec.pdf

Captura de pantalla 2016-02-29 23.56.45.png

ESP8266 to Arduino:
GPIO0 to 3,3V: Through 10K resistor
GPIO2 to 3,3V: Through 10K resistor
GPIO15 to GND: Through 10K resistor
EN to 3,3V: Through 10K resistor
VCC to 3,3V
GND to GND
TX to RX
RX to TX :Through voltage divider resistors (18K ad 10K) in order to decrease 5V (from TX Arduino) to 3,3V (tension that ESP can receive without burning)

While turning on the Arduino and opening the serial ("Both NL & CR" Selected and "115200" Baud Rate) it started to write weird symbols... I thought it could be the Baud Rate, so I tried each of them but nothing happened. Finally I decided to connect RX(ESP) with RX(Arduino) and TX(ESP) with TX(Arduino) and... It worked!!! Now I can write "AT" through the Serial and I get the "OK" confirmation. But I don't understand why...

Does anybody knows why RX-RX & TX-TX combination is working? It has no sense, isn't it? Should I update the firmware? Or it is a Hardware problem of my ESP?

Thank you guys for your help!

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- Tue Mar 01, 2016 9:01 am #42159 This is perfectly logical :

RX/RX and TX/TX means that your ESP is connected to the USB-TTL directly, but in such case the ESP won't be able to talk to ATmega328. RX/TX and TX/RX will make the ATmega328 talk to ESP, but not USB-TTL.
You can NOT have both at the same time.

- Wed Mar 02, 2016 9:35 am #42240 Ok I get it! Thank you very much martinayotte