Hi!

I haven't enough pins in my controller and I need use some fake pin numbers to allow user select the right pin desired if not using a multiplexer.

The problem is that using the pin number as 86 for Arduino Mega the code change pin status of pins 10, 11 or 12.

Here the test code:

void setup() 
{
 pinMode(9, OUTPUT);
 pinMode(10, OUTPUT);
 pinMode(11, OUTPUT);
 pinMode(12, OUTPUT);
 pinMode(86, OUTPUT);
}
void loop() 
{
 digitalWrite(9, HIGH);
 digitalWrite(10, HIGH); 
 digitalWrite(11, HIGH); 
 digitalWrite(12, HIGH);
 delay(1000); 
 digitalWrite(86, LOW); 
 delay(1000); 
}

For this example only the LED on pin 11 is blinking but in my big code I have pins 10 and 12 blinking too.
I think that Arduino core should have a function to ignore wrong pin number to prevent strange behavior when user has wrong pin signed on code.

Best regards.