STEVAL-STWINBX1 examples doesn't respect STM32U585 datasheet

[nicolas]

The datasheet of STM32U585 say that "For operation with voltage higher than Min (VDD, VDDA, VDDUSB, VDDIO2) +0.3 V, the internal pull-up and pull-down resistors must be disabled." (chap. 5.3.1).
The STEVAL-STWINBX1 use a VDDA of 2.75V and a VDD of 3.3V => Min (VDD, VDDA, VDDUSB, VDDIO2) +0.3 V = 3.05V < VDD = 3.3V.
But in the examples provided for STEVAL-STWINBX1, pull up and down are used with a VDD of 3.3V.
So which is correct, the datasheet or the examples ?

[Amel NASRI]

Hi @nicolas ,

Reviewing the product datasheet, I think that you are referring to the following note:

This note is applicable for VIN (the voltage input that may be applied for device pins) and not to VDD:

Therefore, I believe that the STEVAL-STWINBX1 design aligns well with the operating conditions described in the datasheet and in AN5373: Getting started with STM32U5 MCU hardware development.

Additionally, I received confirmation that the STEVAL-STWINBX1 has been used for a considerable time with various firmware and demos without any reported issues.

-Amel

[nicolas]

I'm using SDDataLogFileX with STEVAL-STWINBX1. In the code i saw that pull up are used for I2C2 (I2C2_MspInit). When measuring on the I2C2 pins, i saw a signal that go up to ~3.2V. So for my understanding it doesn't respect the datasheet because it's higher than 2.75V + 0.3V.

[Amel NASRI]

I assume that there is no external voltage input for the I2C pin, so it is normal that the voltage is aligned with VDD.

[nicolas]

I also found it normal but the datasheet say otherwise.

By reading the phrase "For operation with voltage higher than Min (VDD, VDDA, VDDUSB, VDDIO2) +0.3 V, the internal pull-up and pull-down resistors must be disabled.", for me the internal pull up should be connected to the minimum of those VDD so in the STEVAL-STWINBX1 case to the VDDA = 2.75V.