STM32G071 UCPD Dead Battery pins does not work.

[Cagatay]

I have STM32G071 MCU to control a USB Type C hub and I want to use VBUS Powered sink in the application. I have connected Dead Battery pins to their respected CCx pins. It supposed to act as a sink when there is no power but when I connect the type c port to a device, it does not act as a sink and connected device does not give any power. I have activated the Dead Battery signals in STM32CubeIDE but it does not work. Also I have tried activating signals by configuring SYSCFG register but it did not work either. What should I do to make it work?

[waclawek.jan]

> It supposed to act as a sink when there is no power

[...]

> I have activated the Dead Battery signals in STM32CubeIDE

Presumably, that's some code, and that can't influence signals when there is no power, can it.

Dead battery is indicated by Rd=5.1kOhm pulldown on the CCx pins. This pulldown is enabled even in powered-down mcu by the respective DBCCx pins. See the pinout table in datasheet, and read DBCC1 and DBCC2 lines chapter in AN5225.

JW

[HFISTM]

Hello @Çağatay Ertürk​ ,

Can you please tell us a bit more on your hardware setup ? Are you using just a G0 or also a TCPP0x IC in between the G0 and connector ? This would change the needed wiring of db pins.

Considering you are just using a G0, and connected the db pins to the cc pins as you said, you should be good.

As @Community member​ said, you cannot activate the DB behavior by software, as your MCU would not be powered. That is why this feature is enabled by default. In CubeIDE/CubeMX you can disable this feature if not needed, to save on power consumption.

Please refer to sections 7.3.15 and 38.4.6 of the Reference manual for details.

Regards

[Cagatay · Accepted solution]

I have solved the problem. From the source device, two cc lines are simultaneously powered and it confuses the cc lines of the MCU. When one of the cc lines are cut off, It worked.

[Nicolas P.]

@Çağatay Ertürk​ Were you using a standard cable ?

Because normal cable have only one CC line connected from one end to other.

See the wiki here.

[Cagatay]

It was not a standard cable. We designed a flat Type-C cable for an application but we did not consider that it must have only one CC line.