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Topic: MEGA ADK pin layout change??? (Read 908 times) previous topic - next topic


Sep 14, 2012, 03:32 pm Last Edit: Sep 14, 2012, 03:37 pm by Andr01d Reason: 1
Did the pin-layout of the mega adk board change? I have an R3. According to the documentation, 43:INT0 --> DIGITAL pin 21 (SCL)

I ran a simple sketch;

void setup() {
  attachInterrupt(0, goLow, LOW);
  pinMode(8, OUTPUT);

void loop() {
  digitalWrite(8, HIGH);

void goLow() {
  digitalWrite(8, LOW);

the interrupt seemed to be on all the time. I read the reference on attachInterrupt(), it mentions that INT0 is digital pin 2. A quick try using this pin, the code works.

Now I'm confused. Are there other pins that have been changed? I'm going to use the ports to direct read/write... I'm rather concerned if the layout is not up to date.

anyone has this problem?

many thanks,


Interrupt 0 (INT0) on the ATmega chip is not the same as what the Arduino libraries define as Interrupt 0.

This is how the Mega boards have always worked, so I'm confused on what you think changed.
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