Question

Hi,

I want to connect Pmod to Arduino Uno. 

Quote

Any external power applied to the Pmod must be within 1.65V and 3.3V; however, it is recommended that Pmod is operated at 3.3V

From Arduino pins we get 5V so does this refer only to power supply (which we have on Arduino board) or for others pins too? Is it safe to connect it directly to Arduino or I have to use voltage dividerfor other pins?

Thank you.

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Hi @ElectronicsBeginner,

Looking at the documentation tab for the Arduino Uno, it looks like all of it's IO pins operate from 0V to 5V, so I would recommend using a voltage divider to ensure the the 5V signals do not damage the pins that are only expecting 3.3V (or whatever you happen set Vdd in order to power the Pmod).

Let me know if you have any questions about this.

Thanks,
JColvin

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Hello @JColvin,

I would imagine a Pmod logic level shifter with a flow through path would make a good addition to the Pmod line up. The existing Pmod LVLSHFT is not convenient when used with other Pmods. 

I used a Pmod BB with a TXB0108 (https://www.adafruit.com/product/395) to create my own "Pmod Shift". It makes it very easy to use 3.3v Pmods with an Arduino.

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I had noted in my reply that the PmodLVLSHFT is not convenient to use for other Pmods. It is better suited for jtag and fly-wire use.

What I was talking about was a "flow through design" being able to plug an existing Pmod onto one end of the shifter and plug the other end of the shifter into your controller's Pmod port. 

I have done this using either the TXB0108 previously mentioned as well as a TXS0108 which is more suitable for I2C use.

 

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Hi @kwilber,

So you did; probably why I shouldn't respond to posts at home before I get into work proper. I apologize for the confusion.

I agree that such a Pmod with that flow through design would be nice to have, and supposedly it would be fairly easy to design considering we have the hardware side done and it's the form factor that needs some work.

I will pass the suggestion along to the appropriate people at Digilent.

Thanks,
JColvin

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Hello,

I jump in this discussion just to note that Arduino Uno provides, in the POWER bank pins, a "3.3 V" pin.

So I am thinking (without too much knowledge) that this could be used to solve at least the power of the connected Pmod. Still, you should be concerned if this pin provides enough power for your Pmod: https://forum.arduino.cc/index.php?topic=104.0.

I also note that Arduino Due has 3.3 V IO logic level. 

Good luck.

Edited by Cristian.Fatu

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