STUSB4700 - Define USB communication

RenanTesch · ‎2025-01-05

Hello, I implemented a project using STUSB4700 to provide a charge to an Android tablet, the power interface is resolved using this topic https://community.st.com/t5/others-hardware-and-software/stusb4700-constant-output-switching/m-p/734155 because I had the same problem in the first time because I used some 5v for source, but now the power is resolved and I've the second issue, in parallel I use the USB C to communication by USB-serial converter by Android Tablet, but the converter isn't recognized by android, I try found in this document: https://community.st.com/t5/interface-and-connectivity-ics/stusb4700-4710-i2c-register-details/td-p/234334?attachment-id=8852 the register to set the accessory interface in negotiation by CC channel but I didn't have success, can you help me?

In attach my schematic.

Best Regards.

Didier HERROUIN · ‎2025-01-06

Dear customer,

In your use case, the "Nigro" device will be the power SOURCE and the Tablet will be the SINK.

Then, on a data point of view, at connection the data roles must be aligned with the power roles (this is specified by the USB standard): the SOURCE must be the Host (or DFP) and the SINK must be the Device (or UFP).

In your application, could you confirm if the tablet is supposed to be the Host or the device ? If the power and data role are not aligned, you must proceed to a data role swap, which would require another solution, based on a MCU.

Regards,

Didier

RenanTesch · ‎2025-01-06

Hello Didier, thank you for your response.

Yes, nigro is my hardware and this is the SOURCE and tablet Sink, but the tablet could it be a Source or Sink, I can't define it by Android, it's automatic, and this can be a problem in defining data communication?

Best Regards

Didier HERROUIN · ‎2025-01-07

Yes, this could be an issue if the Tablet is supposed to initiate a data transfer (via D+/D-): indeed, the power charging should work correctly (the Tablet should be recognized by the charger as a SINK), but the Tablet can not be a Host for data communication without a data role swap. Unfortunately, as STUSB4700 is a SOURCE only, it is not capable to support this data role swap request (and as a standalone solution, there is no way to "add" this feature from a MCU).

Only a solution based on a MCU can support this data role swap request.

Regards,
Didier

RenanTesch · ‎2025-01-07

Hello Didier, how are you?

Ok, i'll try with STUSB1600, does that work in this case?

I bought the STEVAL-CCC002V1 to test this week.

Best regards.

Didier HERROUIN · ‎2025-01-07

Hello.

No, the STUSB1600 is USB-C only, it can provide 5V only and it does not embed any USB-PD feature (the Data Role swap is a USB-PD feature). It is dual role, but this feature is not really used for 5V product. And if the Tablet is also dual role, the STUSB1600 (and the Tablet) may be randomly Source or Sink, depending on the moment you plug it.

Can you clarify your requirements ?
If you want to design a charger with a single profiles (5V @xA) and you need to initiate a data transfer from the tablet, I would recommend using a TCPP02-M18 with a STM32 embedding a USB-PD stack (STM32 G0 for instance). You will have to set only 1 profile in the STM32 parameters.
Regards,
Didier

RenanTesch · ‎2025-01-07

Hello, can you recommend a STEVAL to resolve this problem?

Can I use another microcontroller without the STM32G0?

Best Regards.