R4 Minima output voltage

Official Hardware Classic UNO R4 Minima
1

Hello to all,
I have an issue with my r4 minima. I measure the output voltage of digital outputs at: 2,5vdc. Is it normal? (For example i cant arm a mini 5v relay)
Also for your info the board works well at programming and etc.
Thanks for your info!

2

Hello and welcome. I've moved your question to its own topic as it does not really relate to the original topic.

Did you use pinMode() to set a pin to output before measuring?

I have no idea what that is but driving relays directly from an IO pin is hardly ever a good idea. Also be aware that the current that the Uno R4 Minima can supply on a GPIO pin is limited to 8 mA (versus the Uno R3 at 40 mA (absolute maximum).

3

Yes I use the bellow:

type or paste code here
```pinMode(6, OUTPUT);
4

That would be normal if you are measuring the output voltage of a pin that was switching between "HIGH" and "LOW" fairly rapidly.

5

I am measuring 2.5vdc at constant HIGH. This isn’t normal I think. Because i tried the same code at the micro and it’s working perfectly.

6

And nothing connected to your board except multimeter?

7

One oled display and a ntc 10k thermistor

8

Disconnect and measure again.

10

I have already tested the same components with another board with exactly same code and they are working perfect. ( nano, micro)

Also I have test the minima with a simple HIGH code and the measurement was the same 2.55vdc without any parts on.

A am using a 12vdc power adapter. The 5v output on the board it’s ok 5.05vdc

12

Did you read that?

14

How much current are you trying to draw from the pin?
That's probably what's dragging the voltage down.

15

Bellow the “simple” high code that I use to test the board.

Without any part connected. I measure at the pin 2 with a fluke 3000fc, 2.55vdc
I use a psu 12v 3A to power the Arduino.


void setup() {
  pinMode(2, OUTPUT);
}

void loop() {

digitalWrite(2, HIGH);
delay(5000);
digitalWrite(2, LOW);
delay(5000);

 }
16

With a 5000mS delay, you would likely be seeing the meter reading alternating between 0V and 5V, unless the meter is reading the average of 2.5V.

Measure the voltage with a constant HIGH on the output, not alternating between HIGH and LOW.

20

Really asking how? There is one way only to connect it.

IMG_8958
IMG_89584032Ă—2268 1.07 MB

IMG_8960
IMG_89604032Ă—2268 1.43 MB

21

When goes to Low the voltage goes to 0. So I will buy tomorrow a new board to complete the project. I will try the uno r3 board. Thank you all for your answers!!!

22

Disconnect the 12V cable, power from your computer to the USB socket. What is the pin 2 voltage?

24

With a usb from my laptop goes to: 2.40 Vdc
With a usb adapter 25w from utility: 2.55 Vdc
I think the board have some issue.

25

I am not arguing with anyone. I am looking if someone has faced an issue like this. Thank you for your time about my problem.

26

What is the voltage on the 5V pin?

27

Is 5.05