Burned Atmega328 with Arduino - serial com problem

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1

I have burned a new 328 with an Arduino bootloader and successfully uploaded the blink sketch.
The problem is with the serial communication: if I upload the below sketch:

/*
 * Hello World!
 *
 * This is the Hello World! for Arduino. 
 * It shows how to send data to the computer
 */


void setup()                    // run once, when the sketch starts
{
  Serial.begin(9600);           // set up Serial library at 9600 bps
  
  Serial.println("Hello world!");  // prints hello with ending line break 
}

void loop()                       // run over and over again
{
                                  // do nothing!
}

I get this on the terminal:

˜~þž
ž`f˜˜€

setup for 9600 baud, but if I take it down to 4800 I get the proper string.
Do you know what can be the issue?
Thanks

2

I have burned a new 328 with an Arduino bootloader ...

How? Using the Arduino IDE? Using avrdude from a command shell?

3

Sorry for not being more specific. I burned using another Arduino as ISP programmer.

4

That probably means you have the fuses set incorrectly and are running from the 8mhz internal clock instead of the external crystal.

5

How to I set the fuses correctly?

6

I got it working by re-burning the bootloader. I had no problem with it until I wanted to use the serial communication, the sketches were uploaded ok and executed as they should. I guess I messed up the first time.
Thank you all for your replies.