I want to interface a Teensy 3.5:
With a RockBlock 9603:
I will give 3.3V input to the Teensy, and 5V input to the Rockblock.
The Teensy is said to be 'all digital pins 5V tolerant'. Does that mean that I can just plug in the Teensy and RockBlock UART on each other and get good functioning? Or does this just mean that the Teensy will not be damaged, but the communication will fail due to the different logics levels?
Of course I could use a level shifter (MAX3323EEPE or similar), but this would be 'yet one thing to add to the design', so if I can do without I would like it.