Electronic – Considerations when using internal pull-up/down resistors


I am working with STM32 micro-controllers. These micro-controllers have the option to set the input pin as pull up or pull down:

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Earlier I used to give external pull up or pull down resistor wherever required but now I am wondering whether I can do away with external components and use the pull down feature of the micro-controller itself.

Will that be a good thing to do?

Is there some use case where I should take extra precaution or not use this feature at all?

Best Answer

Yes... You can... It's a proven feature. If you see pin structure in STM32 Reference manual, you can see that it has required components --

STM32 Pin structure

If this satisfies your requirements, then, you can do away with external components.

Edit Remember that at Power up, Pins will be tristated. If it does not hamper your application, it is good! That's why it's good practise to init IO section first and then go ahead with other peripherals.