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KayalaSandeep
Associate
Nov 11, 2025 9:34 AM UTC
Solved

STM32G474 UART4 RX pin pull up

In STM32G474 UART4 pin no PC11(Rx) is 5 Volt tolerant . If I pull up this pin to +5V with 4.7kOhms then it will affect life or operation of microcontroller? please Suggest.

mƎALLEm
mƎALLEmBest answer
ST Technical Moderator
Nov 11, 2025 9:49 AM UTC

Hello,

According to the datasheet this pin is FT_f which means it's Five volt tolerant with Fast mode + capability.

Fast mode + pins can sustain a current of 20mA:

mALLEm_0-1762854494436.png

Doing the calculation:

5V/4.7.10-3 = 1mA -> far from the maximum allowed (20mA).

So no problem with your config.

 

To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.

4 replies

mƎALLEm
mƎALLEmBest answer
ST Technical Moderator
Nov 11, 2025 9:49 AM UTC

Hello,

According to the datasheet this pin is FT_f which means it's Five volt tolerant with Fast mode + capability.

Fast mode + pins can sustain a current of 20mA:

mALLEm_0-1762854494436.png

Doing the calculation:

5V/4.7.10-3 = 1mA -> far from the maximum allowed (20mA).

So no problem with your config.

 

To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.
KayalaSandeep
Associate
Nov 11, 2025 10:46 AM UTC

Thanks for the reply. But I did the exact process two times in both the cases my controller stopped working and  overheating two time what could be possible reason. First time UART Tx and Rx pins are shorted and second time entire microcontroller is  overheating . Please explain what could be the possible reasons

Andrew Neil
Super User
Nov 11, 2025 10:58 AM UTC

That's a new question - so please start a new thread.

You can post a link here to your new thread so that people can follow; also in the new thread link back to here for reference.

You will need to give more details of your hardware and environment:

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