UART communication problem - serial port monitor

[lukasz_957]

I have a problem with UART communication in my arduino uno r3, empty squares appear before the displayed message, the longer the message, the more of them there are.

I will add that this problem appeared a few days ago, and I have been using the arduino since the end of December, where there was no problem before. I noticed that if I add delay(1000) before Serial.begin(9600) I don't have them anymore. What can I do to keep everything as it was before without adding this delay? What could be the problem;

[J-M-L]

please, please never ever again post pictures of text... Not only they are barely or not readable (esp on smartphones and small screens) nor usable directly for copy&paste but they use up lots of storage and internet bandwidth which contributes to polluting the planet.

➜ do your part and do yourself a favour and please read How to get the best out of this forum and modify your post accordingly (including code tags and necessary documentation for your ask).

[xfpd]

Except for a few messes, this web site (link) did okay on image-to-text (screenreader)... the full result (which could be edited):

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void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
Serial.println("Witaj!");
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}
void loop() {
// put your main code here, to run repeatedly: delay(3000);
Serial.println("Minelo 3 sekundy");
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}
Dane wyjściowe Monitor portu szeregowego X
Message(Kliknij aby wysłać wiadomość do 'Arduino Uno' od 'COM3')
☐☐☐☐☐☐Witaj!
Minelo 3 sekundy
Minelo 3 sekundy
Minelo 3 sekundy
Minelo 3 sekundy
Nowa linia
9600 baud
Wiersz 6, kolumna 2 UTF-8 Arduino Uno na 1COM3 2

EDITED:

void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
Serial.println("Witaj!");
}
void loop() {
// put your main code here, to run repeatedly: delay(3000);
Serial.println("Minelo 3 sekundy");
}

OUTPUT

Dane wyjściowe Monitor portu szeregowego X
Message(Kliknij aby wysłać wiadomość do 'Arduino Uno' od 'COM3')
☐☐☐☐☐☐Witaj!
Minelo 3 sekundy
Minelo 3 sekundy
Minelo 3 sekundy
Minelo 3 sekundy