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Topic: What does the 3.3v running voltage change about how you use the due? (Read 545 times) previous topic - next topic

BenHargreaves

I'm planning on upgrading to a new arduino board from the arduino uno because I need more features and i/o pins. I've been looking at both the mega and due and the due seems best for me since it has audio, scheduling and keyboard/mouse libraries as well as being a lot faster and having more memory. The only issue is the 3.3v warning plastered everywhere the due is mentioned. I don't understand what that changes about how you would use it so I feel uncertain about getting it. I've searched all of the web but I can't find a clear explanation of what it means.

I was hoping that someone could explain how I would have to change my circuits to work with it and what I can and can't do with it.

Thanks in advance  :)

MarkT

You use it with 3.3V devices, or for 5V devices you always have to add a level-shifter
between the Due and the device.

Almost nothing new these days is 5V, all new logic circuitry is 3.3V, 2.5V, 1.8V, 1.2V, ...
This is because lower voltage means faster lower power circuitry. (I'm speaking digital,
not analog devices...)

Fortunately a lot of sensors and similar devices either support 3.3V and 5V, or are
available on breakout-boards with level-shifting built in - the ideal situation.   Often
this is because the device has both analog and digital circuitry and you seldom
see analog circuitry below 3V.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

BenHargreaves

Okay thank you. I think I understand what it means now. Does that mean that I need to use the 3.3v pin for powering my input devices rather than the 5v one?

MarkT

All signals going to Due pins must be restricted to 0V to 3.3V range.  If that's best done
by powering the device at 3.3V then yes, but its not always needed.  Some devices
have configurable I/O voltages, some are inherently 3V but the breakout board has
a 3.3V regulator on it for convenience, etc etc.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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