Reading 3.3V Serial from Standard Arduino

Hello, does anyone know if communicating normally (rx,tx) using a standard Arduino platform with a 3.3V device will be safe without any adapters?

Thank you,
Z

The output of the tx pin is 5V, but at very low amperage. There should be no problem with a 3V3 device having 5V fed to its rx pin.

Zigbee radios are 3V3 devices, and they work fine talking to 5V Arduinos.

To be safe, though, you would need to look at the data sheet for YOUR 3V3 device, to see what it says about its rx expectations.

A 3V3 device sends 0 or 3V3 signals, which the 5V Arduino sees as LOW or HIGH respectively, so that isn't an issue.

So the Arduino RX reads 3.3V just fine for you with the zigbees?

There should be no problem with a 3V3 device having 5V fed to its rx pin.

I beg to differ.
I would use a 100R series resistor to connect them up and have a diode on the 3v3 input (anode), with its cathode to +3v3.

Or you could use:

just to be safe :smiley:

Mowcius