UART receiving problem

Projects Programming
1

The chip is ESP8266.

I see all prints outside like

Serial.println("UDP OK");

Now I want to receive a char from a terminal

void UART_Get()
{
     char chr; 
    if (Serial.available() > 0)
    {
        chr = Serial.read();

        //for debug
        Serial.print(chr);
    }
}

and I put it in loop

void loop() 
{
     UART_Get();
}

But I get nothing.
I'm connected with USB-TTL converter on a development board and not sure if the RX line connected directly to the chip. The TX line I see on a terminal and on the Serial Monitor in Arduino.

2

Maybe this will help:

https://forum.arduino.cc/t/serial-input-basics-updated/382007

3

It's a very good article but actually I'm stuck at basics - receiving a single char. I suspect RX line has some trick cause flashing goes automatically, I don't touch any program related pins. Some RX toggling mechanism.

4

1. If you are uisng only the bare ESP8266 chip or ESP8266 based NodeMCU, you have to map it into Arduino by installing the following package:

http://arduino.esp8266.com/stable/package_esp8266com_index.json

2. Then connect the UART line of the chip to PC via TTL<---->USB converter.
3. Then upload the following sketch:

void setup()
{
  Serial.begin(115200);
}

void loop()
{
  UART_Get();
}

void UART_Get()
{
  char chr;
  if (Serial.available() > 0)
  {
    chr = Serial.read();

    //for debug
    Serial.print(chr);
  }
}

4. Then open the Serial Monitor and communicate with the ESP using InputBox of the Serial Monitor.

5. Serial Monitor outpur using ESP8266 based NodeMCU (Fig-1);.
AQ

nodePic
nodePic640×541 214 KB

Figure-1:

5

I'm not sure how to define the board DOITING ESP-12F - is it the bare ESP8266 chip ? is it ESP8266 based NodeMCU? Any way I have the communication - Arduino burns my code in it (TTL<---->USB converter is located on the board). Do I still have to install the file? If so - how do I do it?

6

Follow these procedures:
1. Connect ESP8266 chip with PC using TTL<-----> USB converter.
2. You need to have Arduino Bootloaded installed in the ESP8266 chip. I don't know how to do it. If you don't know, then begin to learn with the following ESP8266/NOdeMCU Learning Kit (Fig-1 of Post-4).

3. Open the IDE.
4. File ----> Preferences
5. Copy the following text in the box named "Additional Boards Manager URLs:". And then click on OK button.

http://arduino.esp8266.com/stable/package_esp8266com_index.json

6. Sketch ---> Include Librar ----> Manage Libraries... ; Library Manager window will appear. Enter ESP8266 and then click on "install" button when sub-window mentioning ESP8266 based NodeMCU appears.

7

Thank you. The picture looks exactly like my board so I'll try to do this procedure.

8

Then everthing is alright. You don't need any converter. You just plug-in the cable with USB Port of PC. The Kit has bootloader. You just need to install mapping package by following Step-6 of Post-6.

9

I did the following test - connected to external pins RX(GPIO3) and TX(GPIO1) with my external USB-TTL converter. And I see all prints outside but when I type - nothing happens. We can not blame a platform or a dev. board in this case, can we? :thinking:

10

Make connection like below and then follow this link: InstallESP8266 Based NodeMCU.

nodeConn

11

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