Replicating Arduino's serial communication on atmega328p

Question

I have a simple circuit, with an ESP8266 and an Arduino Nano, communicated via Serial.

To test this communication, I send a simple "TURN ON" string and the Arduino should turn on a LED.

This is the Arduino code:

void setup() {
  Serial.begin(9600);
  pinMode(3, OUTPUT);
}

void loop() {

  if(Serial.available() > 0) 
  {
    String command = "";
    while(Serial.available())
    {
      command += (char)Serial.read();
      delay(1);
      if (command == "T"){
        while(Serial.available())
        {
          command += (char)Serial.read();
          delay(1);
        }
      }else{
        command = "";
      }
    }

    if(command == "TURN ON") {
      digitalWrite(3, HIGH);  
    }

    if(command == "TURN OFF") {
      digitalWrite(3, LOW);
    }
  }

  delay(500);
}

This works fine.

Now, I would like to replace the Arduino with an Atmega328p.

I have the basic circuit:

Plus the led, and the TX and RX pins connected to the ESP8266.

If I upload the same code to the Atmega328p, it doesn't work, so I guess I'm missing something very important (like UART configuration or something) but I don't know what that is

Nitro Nitro · Accepted Answer · 2018-05-21T09:23:54

I am guessing that you have used an external programmer with the Atmega328p, and it is a fresh Atmega328p.

If my assumptions are right, then the fuse bits within your Atmega328p are set to use the internal 1MHz clock, and that is causing the problem.

What you can do to fix this: Connect the programmer to the Atmega328p Go to tools>boards, select Arduino Uno in the Boards. Go to tools>programmer select the programmer you are using. Go to tools and select Burn bootloader.

You can then upload your code to the Atmega328p, it should start working the way you expect it to.

I hope this helps.

Replicating Arduino's serial communication on atmega328p

3 Answers