User Manuel(UM1956) of Nucleo-L432KC and Datasheet(DS11451) of STM32L432KC are different.

[SLee.12]

I want to use I2C using Nucleo-L432KC Board.

so, I reading User Manuel(UM1956/ about Nucleo-L432KC board) and Datasheet(DS11451/ about STM32L432KC MCU).

but User Manuel(UM1956) and Datasheet(DS11451) are different.

According to the Table 13 of User Manuel, I2C use PA6 and PA5.

According to the Table 15 of Datasheet, I2C don't use PA6 and PA5.​

STM32CubeMX follows datasheet.

So, which should I follow to use I2C?

[waclawek.jan]

The part datasheet is more authoritative. There is no I2C functionality on PA5/PA6.

However, as the footnote (incorrectly numbered though, it's footnote 2 rather than the indicated 1) says, I2C functionality on those two pins depends on solder bridges SB16 and SB18 being closed (which they are supposed to be by default), connecting A4/A5 to PB6/PB7, which do have I2C functionality. In that case, you should leave PA5/PA6 as Inputs.

JW