5V Tolerant GPIO pins (STM32F030K6T6)

[Nicholas Yunker_2]

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]

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

[AbChen2015]

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]

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

[TDK]

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.

[Nicholas Yunker_2]

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]

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

[Peter BENSCH]

No.

[Uwe Bonnes]

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