int
pin = 13;
volatile
int state = LOW;
void
setup()
{
\xA0 pinMode(pin, OUTPUT);
\xA0 attachInterrupt(0, blink, CHANGE);
\xA0 Serial.begin(9600);
}
void
loop(){
\xA0 digitalWrite(pin, state);
\xA0 Serial.println(state);}
void
blink(){
\xA0 state = !state; }