I've got 2 arduinos connected together with one triggering an interrupt on the other one.
When the master device sets the pin high it reaches 2.4 volts, not enough to trigger the interrupt. Currently I have to touch the interrupt wire with a 5V power supply to get it to work.
I'm using a 20k pulldown resistor attached to pin 2 to keep the signal at 0V when not triggered. I've also tried no pulldown resistor and added a 500 ohm current limiting resistor in series with the interrupt line.
Anybody know what I can do to correct this problem.