UART receiving problem

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.

Maybe this will help:

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

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.

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


Figure-1:

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?

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.

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

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.

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:

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

nodeConn