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Arduino UNO and ESP8266 wrong connection? 5V voltage at RX0 and TX0

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  • Level 11  
    Hello, I need help connecting the ESP8266 WI-FI module to the Arduino Uno R3 board. I connected everything as in the picture:
    Arduino UNO and ESP8266 wrong connection? 5V voltage at RX0 and TX0FC5FW5JIGH....LARGE.jpg Download (53.59 kB)

    And here I have some doubts about the efficiency of the Arduino Uno board, because both the RX0 and TX0 pins have 5V each. As you know, the logic of ESP8266 is 3.3V. The voltage divider is made up to RX0. Shouldn't it be a coincidence that TX0 should have 0V?

    Nevertheless, I connected the module according to this diagram. on ESP8266 only the red LED is lit. AT commands - no response.

    Please help. Personally, I suspect damage to the board, but I'm not sure, because I'm just starting to play with Arduino.
    Do you have a problem with Arduino? Ask question. Visit our forum Arduino.
  • Level 2  
    I fought for a week to connect and update ESP8266 via Arduino UNO. The only thing was I was able to connect through Arduino, but the software update could not go correctly. Finally, I folded and bought a USB UART converter. However, the TX converter also has voltage (3.3V or 5V depending on the jumper setting). I think that without ESP software updates, AT commands will not work.
  • Moderator Design Microcontrollers
    AT commands work in every version to the extent that the software is installed.

    @mr_bl
    The voltage divider should lower the voltage sent from the TX line of the microcontroller to the RX line ESP8266.
    In addition, the lines should be crossed and this is your basic problem: http://mikrokontrolery.blogspot.com/2011/03/Moduly-WiFi-Kurs-komunikacja-mikrokontroler.html

    Also check the table of contents on the above page.

    The RS232 - USB adapter is worth having - it's less than $ 1 with free home delivery from China.
  • User removed account  
  • Moderator Design Microcontrollers
    @ Piotrus_999

    A colleague is just beginning:

    mr_bl wrote:
    Please help. Personally, I suspect damage to the board, but I'm not sure, because I'm just starting to play with Arduino.
  • User removed account  
  • Moderator Design Microcontrollers
    ... but let's give him a chance and remember that we were all once beginners (although there was no access to the network at the time) ... :)
  • User removed account  
  • Level 2  
    Electrode stereotype sustained! It just so happens that in my case I searched everything I found in google. I watched a dozen or so videos and read even more articles in Polish and English (I don't know how the creator of this thread). It wasn't until today (after two weeks of pulling hair out of my head) that I read one sentence that "enlightened" me: "I was using Arduino (ATMEGA328P-PU) with 8MHz at that moment so for UART speed 115200 the error rate is 8.5% hence everything was falling apart. It was enough to adjust the speed with the aforementioned command. " This is the comment from the link that @dondu sent. I changed bps to 9600 and ESP started to communicate with Arduino. Also, @dondu, many thanks :) .

    EDIT: Not really a department ;) .
  • Level 11  
    Well. It turns out that nothing can be asked anymore. I also looked through a lot of literature on the Internet, connected in various ways and unfortunately without effect. Well, apparently not everyone is as brightly enlightened as @ Piotrus_999.
  • Moderator Design Microcontrollers
    mr_bl wrote:
    ... connected in different ways and unfortunately no effect.

    Show pictures how you connect it.
  • Level 10  
    Buddy "mr_bl" slowly ask and believe me that you will get the right help but without exaggeration. Where did you find the diagram to connect the RX pin to RX since it is short for Received? You understand what I mean? Transmission-> Reception and not Reception-> Reception. In addition, I understand a little frustration of colleague "Piotrus_999" because he must answer (without offense) silly questions like "where is plus and where minus" for the "time" enty. And believe me that he has a lot more knowledge and will definitely help you in more serious problems so don't be surprised that he responds in such a tone. Is also right that you read either without understanding or too little information about connecting the module to Ardu because it is full. I suggest you start again from the beginning and slowly move forward because I had, like you, but with a Bluetooth module. TX and RX hardware pins did not work, so I looked for information on the network, three days to no avail, and then used the Software Series on other pins. However, after a while I realized that I would miss these pins for the project so I started looking again for what might be wrong. In the end, to my delight, I solved a problem that was very banal, so to use the RX, TX pins you need to use the "Serial1" command and not the "Serial" itself when communicating with the BT module, of course in my case. Forgive me for the small offtop but I had to write it :)

    Returning to the problem, maybe this page will help you when you have finished connecting.
  • Level 21  
    @Jaceman I also have bad experiences with "electrode stereotype" but a lot depends on ourselves. As I came here for the first time, intimidated by the level of knowledge prevailing on the forum, it did not occur to me to ask about some simple things (as simple as in this thread). It was just a shame. I was googling everywhere and in 99% of cases I was able to find answers without asking questions. this 1% is because I wasn't stubborn enough. Today, young people are different. The Internet makes you lazy and lets you think that on the other side there are always people waiting just to help them. This is not always true. And knowledge is really at your fingertips.
    Why are you surprised By asking a simple question which is a petryliard of threads on the net, you let me know first and foremost about yourself.
    Nobody here is obliged to help. People do it voluntarily when they want to. This must be understood and respected.
  • User removed account  
  • Level 21  
    Back to the topic.
    If you want to connect ESP to your computer using the built-in USB bridge in arduino you really connect TX with TX and RX with RX. Just the descriptions on the arduino board apply to the atmega pins, not the USB-serial bridge.
    However, you have to remember that in this case you have an ATMega connected all the time in parallel with ESP. As for the signals sent from the PC, there is no problem: they go to the inputs of both systems (atmega and ESP) while the outputs of these systems can interfere. Therefore, you should disconnect one of them. Of course, this system will be unnecessary atmega. How to do it. It's easy, put a jumper to ground on the controller reset pin.
  • Level 11  
    The problem is now solved. I bought the simplest USB-UART converter, updated the firmware and ESP8266 responds to AT commands in both Termite and Arduino. Thank you to everyone interested in the topic for the answers.