3.3v midi board with 5v pro micro

Using Arduino Project Guidance
1

Is there any reason why I couldn't use an Adafruit Feather Midi Wing with a 5v Pro Micro? Other than needing to wire the connections instead of using headers, I can't see any problems because midi traditionally runs at 5v anyway, but I suppose some components in the optocoupler circuit might be 3.3v only.

If there are any such problems, could I just use a voltage divider to set the voltage?

I am building a control surface in a foot controller form, so space is at a premium and the Adafruit board is way smaller than normal shields and also doesn't ask me to scratch build a new circuit, so it seems perfect (also cheap!). The actual control surface part of the project is working nicely over USB, I'm just looking to add some flexibility with other midi controllers and have them talk to each other.

2

Draw a quick schematic of how you intend to connect them. Make sure you have level shifters if you are mixing 3V3 and 5V logic.

No.

3

Well, I'm rather asking how (or if) they can be connected.

The only connections out of the Adafruit board are +voltage, ground, tx and rx. So nominally we would be connecting those to corresponding pins on the Pro Micro, and the vcc, with or without something to step down the voltage.

If that doesn't work, that's fine, but a bit more insight than "no" would be appreciated.

4

The answer depends on what connections you want to make.

You can't use resistors to step down the power. You'll need a regulator to make 3V3 unless one of the boards has one built in.

The Tx and Rx will need a level shifter if the two boards are to communicate over those lines.

5

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