STM32U5A9J-DK SPI3_CS Pin

[MMess.1]

Hi

We are using the STM32U5A9J-DK Development Kit.

I want to connect an external device over SPI to the Board using the SPI3 wired to the CN10 Pin see the schematics. As from the datasheet of the development board and also found in the schematics, the pin 16 is routed to PG15 (SPI3_CS)

Using the STM32CubeMX it is not possible to set the SPI3_CS nor SPI3_NSS signal on this Pin.

I just checked the manual of the STM32U5A9J Controller and it look's like it is not a alternate function of this Pin.

I think there is a mistake somewhere, either in the STM32CubeMX or in the Schematics and Datasheet of the Discovery Kit.

[Ghofrane GSOURI]

Hello @MMess.1 

Thank you for your contributions and for your detailed explanations,

I confirm the issue on my side, it has been reported to STM32CubeMX development team .

Internal ticket number:  157861(This is an internal tracking number and is not accessible or usable by customers).

I will keep you posted with updates.

Thx

Ghofrane

[Mike_ST · Accepted solution]

Hello,

As you said, it is an error in the schematic, there is no SPI3_NSS on that PG15 pin.

It is not an error in CubeMX.

Please use another pin where the SPI3_NSS function is actually present, like PA4 (PIN 25/ CN9).

Or use PG15 as a GPIO to do the CS function.

[Tesla DeLorean]

+1 Use as a GPIO,  most STM32 use a GPIO for SPI CS as the peripheral level behaviour with the pin might charitably be described as "unhelpful"