Hi All, I'm using STUSB4500 as USB Type C PD controller. When am connecting type C cable from adapter to the board it is able to power up. But when I remove the cable and connect again it is not powering up.

[Vvk.755]

For the next time I have to re-connect the adapter than re-connecting type C cable for powering the board. Please help me to find a solution for this issue.

Regards,

Vyshnav Krishnan

[Gregory Go.]

Hello,

The issue could be due to the discharge of VBUS after the cable disconnection.

Following the USB-C spec, VBUS must be discharged to VSafe0V, before getting 5V again.

With which board do you have this issue ?

Is it your own board, or the STUSB4500 evaluation board (STEVAL-ISC005V1) ?

Regards,

Gregory

[Vvk.755]

Hi Gregory,

It's our own board. We are using it for PD application as well as for USB 3.0 devices alternately. Below is the schematic design for your reference.

Regards,

Vyshnav Krishnan

[Gregory Go.]

Hi,

The schematic seems OK.

I think the issue is linked to VBUS which is not totally discharged before you connect the USB-C cable the 2nd time.

- Can you check with an oscilloscope the VBUS voltage when the cable is disconnected, on both side of the application (i.e. on the Source side and Sink side).

And then capture how VBUS behave when you connect the cable again.

- Capturing also CC pins (CC1 and CC2) on STUSB4500 side can also help to understand what is happening.

Best Regards

[Vvk.755]

Hi Gregory,

I'll check it and get back to you. Is there any register settings required for NVM for proper discharging.

Even USB 3.0 device is not getting detected. The A_B_SIDE signal of STUSB4500 is used for selecting 3.0 driver IC. When I connect USB3.0 Device its detecting as high speed device not as super speed device.

Regards,

Vyshnav Krishnan

[Gregory Go.]

Hi,

Even USB 3.0 device is not getting detected. The A_B_SIDE signal of STUSB4500 is used for selecting 3.0 driver IC. When I connect USB3.0 Device its detecting as high speed device not as super speed device.

- The USB 3.0 Data interface is independent of the USB PD controller.

So you need to configure properly your USB 3.0 controller if you want to use USB 3.0.

- Check the USB-C cable used

If you use a basic USB type-C 2.0 cable, it won't support USB 3.0.

For USB 3.0, you must used a full-featured USB-C cable. I.e. an EMC cable (Electronically-Marked Cable).

- Do you have a Super-Speed switch in your schematic ?

This is required for USB 3.0 support.

- How did you connect the USB 3.0 wires (SSTX/SSRX) ? Because I don't see then on your schematic.

Regards,

Gregory

[Vvk.755]

Hi,

Can you please verify this.

Regards,

Vyshnav

[Gregory Go.]

Hi,

• Regarding USB 3.0:

The schematic looks correct.

The issue for USB 3.0 may come from the Superspeed MUX. It could be a signal integrity issue, which can be tuned with CNFG_A1, CNFG_A2, CNFG_B1, CNFG_B2.

Please contact the TUSB542 vendor to get help with USB3.0 issues.

• Regarding the board not powering up sometimes:

You can diagnose the status of STUSB4500 device by using the STUSB4500-GUI software (in the dashboard panel).

https://community.st.com/s/contentdocument/0690X00000AADwyQAH

The STUSB4500-GUI requires a NUCLEO-F072RB board.

https://www.st.com/en/evaluation-tools/nucleo-f072rb.html

So you need to connect the I2C pins of NUCLEO-F072RB to the I2C pins of the STUSB4500 IC located on your hardware.

Then, using the diagnostic tool, you can check the error condition which makes the board not getting power.

Regards

[Vvk.755]

Hi Gregory,

Thank you for your quick response. I'll check those things and try to solve the issue.

Regards,

Vyshnav Krishnan