5V Tolerant GPIO pins (STM32F030K6T6)

Nicholas Yunker_2 · ‎2022-02-16

I am interfacing a 5V PWM signal with an STM32F030K6T6 MCU using PB0. According to the datasheet this pin is 5V Tolerant. In the past, regardless of a pin's "tolerance" to 5V I have always used a level shifter to change this 5V signal to a 3.3V signal before it gets to the MCU; "Just to be safe". This application I am trying to limit the number of parts on the PCB for both size and cost reasons. Testing on a Nucleo board seems to work and the MCU seems to tolerate this well, but for long term use in the field is it better to run this signal through a level shifter or does it not matter since the pin is "5V Tolerant"?

Peter BENSCH · ‎2022-02-16

As long as you operate the GPIO as a digital input and switch off its pull-up and pull-down, it can process 5V signals.

Does it answer your question?

Regards

/Peter

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Peter BENSCH · ‎2022-02-16

As long as you operate the GPIO as a digital input and switch off its pull-up and pull-down, it can process 5V signals.

Does it answer your question?

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

TDK · ‎2022-02-16

The chip needs to be powered in order to be 5V tolerant, but if you can guarantee the chip won't see 5V unless it's powered, there are no issues.

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Nicholas Yunker_2 · ‎2022-02-16

Yes, this answers my question. I am not using any internal pull up or pull down resistor on this pin. It is only being setup as a GPIO Input in external interrupt mode:

Nicholas Yunker_2 · ‎2022-02-16

the 5V signal won't damage the MCU over time?

Peter BENSCH · ‎2022-02-16

No.

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Uwe Bonnes · ‎2022-02-16

As long as the device is powered while 5 V applies!

AbChen2015 · ‎2023-09-27

I am totally confused. According to DS5792 Rev 13, page 89, note 1:

FT = Five-volt tolerant. In order to sustain a voltage higher than VDD+0.3 the internal pull-up/pull-down resistors must be disabled.

This is opposite to what you said.

AbChen2015 · ‎2023-09-27

Sorry, you were right by "switch off", which means disable.

Chubs · ‎2023-12-15

Hello @Peter BENSCH & @TDK ,

It may seem redundant - but to confirm can we interface a 5V UART Input signal to the UART Rx pin which is 5V tolerant ie FT? As UART is Push-Pull assuming the Pull-up & Pull-down are disabled by default & the GPIO is configured as input only. Any other things to be aware of? The maximum speed shall be upto 4Mbps.