Tx/Rx voltage pin of Arduino Mini Pro 5V

Good evening.

I am working on LoRa projet and I am using a Adafruit Feather MO LoRa board of 3V.

I need to controll two servo and I could make it worling with an Adruino Mini Pro 5V and not with a Trinket Pro 3V.

As the Arduino Mini Pro is a 5V/16Mhz, I gess the I/O pin has a HIGH level of 5V. That right?

So if I connect

Mini Pro 5V Tx pin to the Feather LoRa 3V Rx pin, and Mini Pro 5V Rx pin to the Feather LoRa 3V Tx pin,

it will not work? That right?

Regarding the Rx and Tx pin of the Arduino Mini Pro 5V, is there a voltage to consider?

Many thank for your clarification

Cheers Pierre

This is a common connection for Bluetooth. A 1k/2k voltage divider on Arduino Tx ensures a 3.3v signal on device's Rx. Arduino can read a 3.3v signal OK, so there is nothing to do

Hello Thank for your reply.

I did not understand all

This is a common connection for Bluetooth.

I never spoke about bluetooth. Never mind :)

A 1k/2k voltage divider on Arduino Tx ensures a 3.3v signal on device's Rx. Arduino can read a 3.3v signal OK, so there is nothing to do

Should I do the divider, or the is nothing to do?

I supposed, I should have 2x1K and 2x2K to do the divider on TX and RX of the 5V devise

pierrot10: I never spoke about bluetooth. Never mind :)

I think @Nick_Pyner was just trying to say that this problem arises with Bluetooth modules and the solution for that will work for your project.

I supposed, I should have 2x1K and 2x2K to do the divider on TX and RX of the 5V devise

As Nick said, you just need the divider between the 5v Tx and the 3.3v Rx. The 5v Arduino's Rx will be able to read the 3.3v Arduino's Tx.

...R

Dear Robin,

Thanks for your clarification!

Cheers