Using integrated DB function of STM32U5 with TCPP01-M12

[EniRot99]

Hello everyone,

I'm currently working on a USB Type‑C Power Delivery design using the STM32U575VGT6Q and the TCPP01‑M12. According to the TCPP01‑M12 datasheet and the example from the UM2581 STM32L5 Nucleo Board, the DB pin should be connected to a GPIO pin on the MCU.

The MCU provides two DB signals to properly indicate a dead battery condition. Can these signals be used and fed to the TCPP01‑M12 DB pin?

However, I cannot find any option in CubeMX to select or configure just one DB signal – it appears that this specific configuration is not available in the graphical interface.

Has anyone encountered this issue?

Should the second DB signal be connected together with the first one?
Should I leave it unconnected or tie it to a defined potential?
Is stacking of an external interrupt on the second DB signal a suitable workaround to use it for the FLT signal?

Thanks in advance for any help!

[FBL]

Hi @EniRot99 

For this nucleo board, TCPP12 is responsible of Dead Battery feature.

However, as you mentioned, STM32L5 MCU provides two DB signals to feature a dead battery without protection (which is not highly recommended) 

To implement the board setup on MX, you need to enable TCPP software package.

[EniRot99]

Hi @FBL 

So do I understand it right, I don't need to use the mcu peripheral, since TCPP01-M12 handles it in this case?  

In this case I connect the DB signal input from TCPP01-M12 with a pullup resistor to VBAT and is handles every thing by it self? 

[FBL · Accepted solution]

Hi @EniRot99 

Well, not exactly! You won't need dead battery pins provided by the MCU peripheral (UCPD), since TCPP01-M12 protection handles it. For further information, check section 6.5 How to handle dead battery (DB) condition with the TCPP01-M12 in Datasheet.