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USB EZ-PD Type-C

Razor6412
New Contributor II

I am implementing a design that follows the CYUSB4357 reference design from the evaluation board.  The buck/boost switcher controllers NCP81239MNTXG and NCP81239AMNTXG are in short supply. I was able to get a good quantity of NCP81239MNTXG, but cannot find any of the NCP81239AMNTXG until November.  I am considering loading the NCP81239MNTXG in place of the NCP81239AMNTXG, but it will have an I2C address that clashes with the NCP81239MNTXG.  If I cut the I2C signals that were going to the NCP81239AMNTXG, what will the hub software do if it can't communicate with that part?

 

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1 Solution
Sananya_14
Moderator
Moderator

Hello,

If the hub firmware isnt able to communicate with the NCP81239AMNTXG because the traces are cut, it will not be able to enable the buck-boost and set the voltage so the PD contract on DS1 would fail. Please refer to the power_control.c file in the HX3PD firmware where you could remove the I2C writes for DS1 provided that you have VBUS enabled at 5V from the buck-boost and have the same source PDO configured in HX3PD.

Additionally, please see if its possible to add an address translator on the I2C lines for DS1 so you could keep the firmware unchanged except for the slave address.

Best Regards,
Sananya

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2 Replies
Sananya_14
Moderator
Moderator

Hello,

If the hub firmware isnt able to communicate with the NCP81239AMNTXG because the traces are cut, it will not be able to enable the buck-boost and set the voltage so the PD contract on DS1 would fail. Please refer to the power_control.c file in the HX3PD firmware where you could remove the I2C writes for DS1 provided that you have VBUS enabled at 5V from the buck-boost and have the same source PDO configured in HX3PD.

Additionally, please see if its possible to add an address translator on the I2C lines for DS1 so you could keep the firmware unchanged except for the slave address.

Best Regards,
Sananya

View solution in original post

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Razor6412
New Contributor II

Thanks, this helps!

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