STM32U5G7VJT6Q - 5V-tolerant pins (FT_h) for Hall encoder

[NIVI]

Hi,

MCU planned to use - STM32U5G7VJT6Q

Planning to use PD12,PD13,PE0,PE3,PC7,PE5 as encoder and hall sensor pins as shown below in the image.

But these signals are 5V logic. Is it okay if we give 5V to these pins?

In datasheet it is mentioned as 5V tolerant pins(FT_h). Does it affect its performance? any AC/ DC characteristic issue will rise because of this. Please confirm.

Or suggest which pins can be used or any other alternate way. Also the possible failure cases.

[AScha.3]

Hi,

the 5V tolerant pins(FT_h) can be used with signals 0..5V , ok.

But i prefer not to relay on some "can tolerate" = can survive , just spend a resistor more:

Then you know, signal is ok for a 3v3 cpu - and some small spike on input does nothing bad also.

(And you can use all pins, not only 5V tolerant pins.)

[Danish1]

St say "5 Volt Tolerant" because they guarantee that no harm will be done and things will behave properly when you apply 5V to the pin as long as Vdd is also powered as described in the data-sheet. So you have to be careful about power-up and power-down sequences.

But when those pins are programmed to be outputs they will only drive as high as Vdd which, of course, is less than 5V. So they aren't true 5V GPIO.

[NIVI]

Thanks danish.

What if those pins are only inputs( Hall sensor and Encoder signals)?

Will it cause any issue or possible failure cases. Please do list it out.

[NIVI]

Thanks Ascha.3

What if those pins are only inputs( Hall sensor and Encoder signals)?

Will it cause any issue or possible failure cases. Please do list it out. Planning to reduce the PCB area. This might be helpful if it can work without any issues.

[AScha.3 · Accepted solution]

>What if those pins are only inputs

Hey, all this "xx tolerant" is only about inputs !! No output is "tolerant" to incoming signals, esp. > VDD .

So spend some cent more and a resistor - or save a cent and test the 5V-tolerance.