Hi Joerg.
I have some strange problem with my setup ( Arduino --> Raspberry ). The system is working perfect but after minute or two, i get HIGH state on RSP pin, but nothing wasn't sent from arduino. I get this states all the time and i can not stop them. They are activated at random cycles.
The funny part is that i can not detect any voltage change ( when this error starts ) and according to the datasheet, voltage from 2.8 - 3.3 is defined as HIGH state.
So, is it possible that RSP is picking some fast impulse from arduino's voltage divider ?
GM