Why does the fifth pin of port D stay on?

[MMust.5]

STM32F407

Why does the fifth pin of port D stay on?

Here is the code:

RCC->AHB1ENR|=RCC_AHB1ENR_GPIODEN;

GPIOD->MODER&=0UL;

GPIOD->IDR&=0UL;

There are 3 volts on pin 5 of port D (I checked with a multimeter).

The IDR register looks like this: IDR: 0000 0000 0010 0000

The ODR register looks like this: ODR: 0000 0000 0000 0000

[Tesla DeLorean]

Probably board related

[Javier1 · Accepted solution]

You didnt specify , but if you are using a STM32F4DISCOVERY board (making a guess here).

The Pin D5 is tied to the USB otg current sense, this could be the reason youre unable to see 0v. (remove the R50 bridge to release that D5 from the usb otg IC )

 

https://www.st.com/resource/en/schematic_pack/mb997-f407vgt6-c01_schematic.pdf

[MMust.5]

The best of the best

[Piranha]

You have one hell of a top-notch crystal ball!

[Javier1]