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CWei .1
Associate II
January 9, 2026
Solved

USB-C PD: STUSB4500 FTP_KEY changable?

  • January 9, 2026
  • 2 replies
  • 272 views

Hello ST

I would like to ask about is it possible to change the STUSB4500 FTP_KEY default values through SMBUS interface? If its possible, could you suggest the appropriate step to do so?

Best answer by Didier HERROUIN

Dear CWei.1,

The procedure to write/read the registers is fixed, including the FTP_KEY values.

2 replies

Didier HERROUIN
Technical Moderator
January 9, 2026

Dear CWei.1,

I am not sure to understand your request.
Actually, when you need to access the STUSB4500 registers, as a first step, you must write the customer access key into the FTP_KEY register using the I2C bus.

This procedure is described in the document attached. Does it answer your request ?

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CWei .1
CWei .1Author
Associate II
January 10, 2026

Hello

I have reviewed the document. Could you please clarify whether the default values of FTP_KEY are fixed, or if they can be modified and configured to user-defined values?

Didier HERROUIN
Didier HERROUINBest answer
Technical Moderator
January 12, 2026

Dear CWei.1,

The procedure to write/read the registers is fixed, including the FTP_KEY values.

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.