Adding IR receiver to busy mega2560. I used the referenced pins for digital input and pin 18 for an interrupt from the receiver. The interrupt service routine always worked as expected, the digital inputs worked erratically 5% of the time. Spent a lot of time chasing possible hardware problems and staring at the software too much. On a hunch, I moved the 4 lines over to pins 2 (interrupt 0) and 3,4,5 for data - now works perfectly. The wire library is being used for I2C which works flawlessly and the lcd library for a 16 x 2 display. If it has been stated somewhere, I haven't seen it, is it a no-no to use the RX2, etc pins when the wire services are turned on. I assumed these pins were available for general use. Like I said above, 5% of the time it did work as expected. Any thoughts?