It works perfectly with a hex inverter but on the long run i prefer to exclude this part. As a matter of fact i'm using a led ring with 16 leds that is mounted very close to the board. So i'm fairly sure this will work without the driver. Anyway i didn't find any single channel schmitt inverters, at best i can use a dual channel package.
I did not try the oscillating pwm yet but it sure sounds fun. I will give it a go this week.
Thanks again.
At the moment I'm still a bit struggling trying to get my toolchain to a newer version and now the linker is protesting with very vague reports.