How to disable internal PU/PD resistor in stm32

samir2 · ‎2016-10-19

Posted on October 19, 2016 at 16:39

Hi everybody,

I just connected one resistor in pin PA3 of stm32f091 to read value of a voltage divider.

But when i connected this, my tension is down.

I know there are pull up and pull down internal resistor about 40 kOhms in each pin, but in output mode ou input mode, the result is the same.

Any idea ?

The register GPIOC->PUPDR is setting correctly.

Thank you

Tesla DeLorean · ‎2016-10-19

Posted on October 19, 2016 at 17:15

Using an ADC or looking at VIL and VIH?

Use the NOPULL setting, for analogue removing the Schmitt Trigger use also AIN

The PA pins are not on GPIOC

Your own custom board, or something else? Any thing else connected to the pins of interest.

Please be more comprehensive with your presentation of the system, the code configuring it, and the values from the corresponding registers.

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samir2 · ‎2016-10-19

Posted on October 19, 2016 at 17:34

Here a schematic of my project.

I don't use it with ADC but with Vil and Vih.

I use PA3 in GPIO

A

Thanks

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