Sorry all, I hit send when I meant to delete what I had partially written yesterday evening.
Not a completed thought, and I didn't think my comments would really be of much help.
But since I did send:
With the specified switch point of Nano's input buffer at 60% of Vcc,and assuming Nano running at 5V,? the Teensy and Nano aren't compatible by min spec.
With a capacitive load, the Teensy should drive to 3.3V rail.
Sascha, I think you are on the right path. Also consider switching speed / baud rate.
Again my apologies,?
Gary
