I2C channels as pull-up in STM32F103C8T6

hdhdhd · ‎2024-04-30

Hello everyone,

I want to configurate the I2C channels as pull-up in STM32CubeIDE for STM32F103C8T6, but I couldn't set it.

It looks like in the attached image. It just shows n/a in configuration.

How I set it as pull-up?

Please inform me. Thanks.

Andrew Neil · ‎2024-04-30

The internal pull-ups are not suitable for use as I2C bus pull-ups - you need to use external pullups.

EDIT:

See this post for the effect of too-high and too-low pullups:

https://electronics.stackexchange.com/a/473799

FBL · ‎2024-04-30

Hi @hdhdhd

Internal pull-ups are not recommended for I2C. Pull-ups must be adapted to the I2C bus speed and to the bus load.

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AScha.3 · ‎2024-04-30

Hi,

i just tried , yes, on F103 no pullups to set , only n/a .

But on F401 i tried also, here pullups possible :

So for pullups - take another cpu . :)

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Andrew Neil · ‎2024-04-30

@AScha.3 wrote:
So for pullups - take another cpu . :)

Or just use the proper external pullups - the internal ones (when available) are likely to be too large.