This step took way longer then I exoetced. First of I still dont know if the chip was broken or the wirring was wrong but after recabling everything and replacing the chip everything worked as intendet. Getting the communication right was a bit tricky and needed some trial and error as the spec sheet was sometimes not clear enough.

This is the little program I made to test everything: https://gist.github.com/mcenderdragon/3bedb84c0109d7eab66db9308868d196