Serial communication with Arduino (3.3 vs 5v ttl)

Getting Started
1

Hi, im very new to the Spark Core (im very familiar with Arduino and similar boards).

I want to be able to connect my Spark Core to an Arduino board via Serial so that I can send commands between them but there is the issue of the voltage difference (3.3V vs 5V).

Is it possible (and safe for the spark core) to connect the D0 and D1 pins, which are 5V tolerant (using serial2) to the Arduino TX and RX pins in order to send commands between each other.
If not, what is the best way of connecting the Spark Core to an Arduino by serial (aside of using a logic level converter).
Thank you! :slight_smile:

2

Here is a forum post discussing it…

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Have you seen this and this thread?
There are also other threads, when you search for 3.3 or 5V, you’ll find plenty.

@Hootie81 obviously beat me to it :wink:

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hi! yes, i did find those threats but i couldn’t find any confirmation when using serial2 on pins D0 and D1. I asume it should be ok since those pins are 5V tolerant. I just wanted to make sure before something smoked…
I’ll read them again though, in case i might have missed something!
Thanks!

5

OK, as I reread the threads mentioned, I’m pretty certain that you don’t need to go via D0/D1 when you use a voltage divider (200 + 330 Ohm) or a LED (min 1.5V forward drop) in the Arduino TX -> Core RX line and make sure that the Arduino RX never gets driven high.
On D0/D1 you are save without these, but I’d still put the LED or voltage divider into place.
5V-tolerant is nice to know, but better design for the spec voltage :wink:

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Good to know, yeah, i guess it’s always best to design for the spec voltage. Thank you!!
:wink: