Can the Teensy 4.1 handle 5V TTL serial on the UART?

[Dsolberg8132]

I am porting an application from an Arduino Mega to a Teensy 4.1. This application communicates to a 5 volt TTL serial port. Can the Teensy 4.1 handle this or do I need a level shifter?

Don

 

[BillFM]

You need a level shifter for Teensy 4.x.

 

[aleglakov]

You DO need it! Teensy 4.1 handles 3.6V max on all pins except USB ones AFAIK

 

[Dsolberg8132]

Please disregard, I found out on another forum that the TTL output that I want to interface to is in fact 3.3V

Don

 

[BillFM]

According to 1060 electrical manual, GPIO max input voltage is limited to whatever voltage is presented on NVCC_xxxx supply rails. In the case of Teensy 4.x, this is 3.3V.

So, don't present a voltage >3.3V to ANY of Teensy pins.
@aleglakov is correct if Teensy was powered from 3.6V, but it's not.

@Dsolberg8132, if you provide details of the serial device you are connecting to Teensy, we can most likely confirm it's serial input/output voltage levels.