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SPI1 and I2C1 pins are conflicting in the STM32H563

Associate II

Hi Team,


I am trying to use the SPI1 and the I2C1 simultaneously in the STM32H563ZI. Upon configuring the relevant pins in via cubeMX, I see that there is a conflict with the PB5 Pin. I want the PB5 to act as an SPI pin, whereas configuring I2C1 doesn't allow me to do that and I see a warning message for the same. However, I do not have any I2C functionality mapped to the PB5 pin.


Reading up on this, I came to know that there are a few points mentioned on these lines in the errata sheet of a few parts, but the errata sheet of STM32H563 doesn't mention anything on the pin mapping conflicts. Is the issue present for the STM32H563 as well? 


Any leads on this would be of help. 


Thank you,



How you see conflict ? Red or yellow? Yellow is ok only info about possible conflicts...

Hi @MM..1 - Thanks for getting back to me on this topic. It's a yellow mark (attached below). This goes away when I disable the SPI1 peripheral. But the requirement on my end needs both SPI1 and the I2C1.



Thank you,



ST Employee

Hello @Jansunil 

When you use PB5 as SPI1_MOSI, you can keep using I2C1 just in I2C or SMBus-two-wire-Interface.


But when you want to use I2C SMBus-Alert-mode, you need to use I2C1_SMBA pin whish is mapped only to PB5.


To avoid this problem, you can use PA7 for SPI1_MOSI.

Best Regards.


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