Photon TX and RX pins tolerance

So I’m working on a project that is pretty time sensitive and am needing to know if I can safely communicate via the TX and RX pins with an Arduino Uno to a Particle Photon. Are the Photon’s TX and RX pins 5 volt tolerant? I am needing an Arduino to send data to a Photon. Any responses would be appreciated. If this question has already been asked and answered please direct me to that thread and I will delete this one.


Specifcally It says all pins are 5V tolerant except A3 and DAC. I’d want a second opinion from someone smarter than me on it, though.

The other thing you need to check is that the Vih(min) level of the device you’re talking to is satisfied with the Photon’s 3.3v output level. This can be found in the electrical characteristics section of the datasheet.

Vih(min) is the minimum voltage at which the receiving device decides it’s seeing a logic 1 (high) level. As I remember, the ATMEGAs at 5.0v have a Vih(min) of 3.0v so you should be fine.

I was able to get a Core to talk serial with an Arduino Mega 2560, so I can confirm!