TUSB1210: Force USB Device Mode without connected VBUS

Holger Kaplan

Part Number: TUSB1210

Hello TI-Support

We face the following problem inside our application. Our system provides the possibility to act as an USB 3.X device including USB-PD handling, which is not handled inside the device itself - this is done via a special additional electronic. As we could reach up to 20V here, it is not possible to connect the VBUS directly to the VBUS pin of the TUSB1210 and the other electronics on our used SOM (limited in terms of Umax). But we have connected the ID Pin (Pin 23) to a dedicated MCU, which we could control dynamically in respect to the handled sink/source of our USB-PD controller. No we face the issue that we can't connect our system as an USB Device to another Host. USB HOST mode (connecting e.g. To a flash drive) is working.

Is there any possibility to force the TUSB1210 to USB device Mode without connected VBUS?

Some additional information:

CPEN is connected to a Charge Pump --> controlled by TUSB1210

SOM is connected via ULPI interface

ID Pin is connected to a dedicated MCU, which enumerates HOST/DEVICE via teh USB-PD controller (UFP/DFP)

We use the dwc3 dts inside our SOM

Thanks a lot in advance for a positive answer :-)

Holger

6 days ago

0 Vishesh Pithadiya 5 days ago

TI__Guru 55716 points

Hi,

Holger Kaplan said:
Is there any possibility to force the TUSB1210 to USB device Mode without connected VBUS?

The Vbus pin is rated for up to 20V. Why can we not connect Vbus to the pin of TUSB1210?

0 Holger Kaplan 5 days ago in reply to Vishesh Pithadiya

Prodigy 30 points

We have other electronics on this VBUS path, which is not rated up to 20V. Therefore it is not possible to connect it. The USB PHY itself could handle it.

0 Vishesh Pithadiya 4 days ago in reply to Holger Kaplan

TI__Guru 55716 points

Hi,

We are confirming internally and will get back to you shortly.

0 Vishesh Pithadiya 3 days ago in reply to Vishesh Pithadiya

TI__Guru 55716 points

Hi,

The ID pin puts the PHY in device mode. The device needs to detect Vbus per USB spec. Do you have another free GPIO pin in your system? You may be able to use that for Vbus.

0 Holger Kaplan 3 days ago in reply to Vishesh Pithadiya

Prodigy 30 points

Thanks for the reply. We don't want to have a HW change when it is not necessary. We know that the standard says that VBUS needs to be detected. Therefore as an idea:

1. Set the PHY via the ID pin into device mode

2. Force a register entry (I think there must be a entry inside the register set that "indicates" a connected VBUS) OR take the VBUS of the charge pump, which is taken for the USB HOST Mode and connected to the VBUS of the PHY to fake the signal

Or is there any debug mode of the PHY to overcome this issue?. The USB Device mode is an edge case for us. Thanks a lot for helping again.

0 Vishesh Pithadiya 2 days ago in reply to Holger Kaplan

TI__Guru 55716 points

Hi Holder,

We will confirm internally with our design team to see if it is possible to overwrite the physical Vbus status with a register write. We will get back to you once we have an answer.

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TUSB1210: Force USB Device Mode without connected VBUS