Are Serial 2 Pins on Photon 5v Tolerant?

photon
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#1

@rickkas7 or anybody on here know if the Serial 2 RX pins are 5v tolerant or not?

I need to try the RX on Serial2 port since I’m seeing issues using Serial1 + Softserial at the same time.


#2

Yes, they are 5V tolerant.


#3

Thanks for the quick response :particle:

Are the Serial 1 TX and RX lines also 5v Tolerant I assume so but want to confirm since I didn’t see the TX/RX pins listed in the Photon Datasheet unless they are throw in the Digital I/O line up which would mean they are 5v tolerant.


#4

The RX and TX pins (Serial1) are 5V tolerant. They’re not a 5V TTL serial port since the TX pin only provides 3.3V, but assuming the other side tolerates 3.3V for high level (most do), then you’ll be fine.


#5

Good to know.

For this project I’m using the RX ports for receiving data and not using the TX ports to send data.

I only removed the BLUE LED / Serial2 RX resistor since I’m needing to read the RX line but I wanted to ask if I should also remove the Green LED/ Serial2 TX resistor also if I’m not using that port for this project.

I’m guessing I’ll still get some LED light patterns with Green & RED vs. just removing them all.

Was wondering what your advice is as far as removing the resistors.


#6

Since you are only using RX, you only need to remove the one resistor.

If you use both RX and TX you need to remove the two resistors. I removed all three because with only one LED working the color patterns are useless.