With the source code below, I'm getting what I think to be strange behaviour with the serial port output.

void setup() {

int c = 0;    
void loop() {

Presumably what this will do is starting printing incrementing numbers, one on each line, starting from 0. However, my serial monitor only starts printing these numbers after the 3000 mark. I found this behaviour only after discovered in another sketch that I was losing data at the beginning.

Is this normal Arduino behaviour? Or a serial monitor problem? Or something else?

  • Is it consistent? Does it always begin at 3000? And does it continue as expected (3001,3002,...) after that? – SoreDakeNoKoto Mar 5 '16 at 0:36
  • There are many Arduino models. It helps considerably to state in the question which one you are using. – Nick Gammon Mar 5 '16 at 6:26

Is this a Leonardo or Yun? If it is, you have to wait until the Serial object says the USB connection is really ready:

void setup() {
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB

Read this.

Because you did't wait, your loop is able to execute 3000 times before Serial actually sends something back to the PC.

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