My Wiznet812MJ is 5V tolerant I/O (according to datasheet). I'm using SPI. My Atmega is running at 5V and Wiznet812MJ is 3V. Does that mean I can connect the Wiznet812MJ I/O to my Atmega directly without damaging the Wiznet812MJ or shorten its life?
I cant run my Atmega at 3V because other devices running at 5V too.
The word "tolerant" makes me a bit worry. If it say 5V-compatible, then I pretty sure it is no problem.