Interrupt does not read stable

Projects Programming
1

Hi,

I have created a first testscript to start working with interrupts. I have uploaded the code below into my aruino uno (pin 2).

When I put a 5v current the ISR triggers once as it should be and works correct. The strange thing is, when I remove the 5V current I get new ISR calls serveral times and after a while it stops and the processing becomes stable again.

I'm I doing something wrong that triggers the ISR when the current is removed?

int pin = 2;
volatile int state = LOW;

void setup()
{
  attachInterrupt(0, blink, HIGH);
  Serial.begin(9600);
}

void loop()
{
  Serial.println(" loop......");
  delay(1000);
}

void blink()
{
 Serial.println("ISR ");
}
2

You do not do Serial.print() in an ISR
Read:

The strange thing is, when I remove the 5V current I get new ISR calls serveral times

Probably do to a bouncy input.

3

So, any time pin 2 is HIGH, call the interrupt service routine?
Did you read anywhere that doing serial I/O in interrupt context was a Bad Ideatm, because serial output depends on interrupts, which are disabled in interrupt context?

4
6

Also it helps us to see a schematic and or image of your circuit.