EVAL-SCS001V1 Sink Voltage setting

[NAmam.1]

Hello,

I am playing with the EVAL board

EVAL-SCS001V1, NUCLEO board, and the STSW-STUSB002 GUI software.

I am using the PD SOURCE as Globetek Power Module(RR9LZ3000USBCG2(R6B)) , It is generating 20V output voltage at the EVAL board terminal block J10.

Now I would like to change this voltage to 12V, I am thinking I should change PDO3 setting.

I read the contents of PDO3 (REG. 0x8D – 0x90) as 0x00064064 (Reg 8D value is 0x64 just to clarify the order),

So I changed the PDO3 contents to 0x0003C064, and verified the write operation by reading back the contents. I am using the GUI software READ/WRITE I2C Data TAB to alter the contents.

Then I saved hit the GUI software button by pressing “Write NV RAM�?, I got a message saying Write success.

Then I recycled the power to everything, but I am still getting the 20V output and PDO3 setting went back to 20V.

I am not really sure what I am missing here, please advise.

Thanks,

Naga.

[Winfred LU]

The register settings will not be restore after a power recycle.

What you need would be to configure NVM.

It can be configured directly in STSW-STUSB002 GUI :

Then, please remember to write the modification NVM.

The corresponding content is at offset 0xE1 and 0xE2 -- SNK_PDO_FLEX2_V.

To set the voltage to 12V:

• offset 0xE1 = 0xF0
• offset 0xE2 bit[1:0] = 0b00

Which means SNK_PDO_FLEX2_V[9:0] = 0x0F0 = 240

[NAmam.1]

Hi Winfred,

Thanks for the response, before I was referring the document "The STUSB4500 software programming guide - UM2650", Section 1.4 "HOW to fill the PDO registers". I think it may be misleading little bit.

And your explanation is matching with STUSB4500 Datasheet section 5.2 "Default Start up configuration". I think your EVAL board quick start guide requires more info like "How to set the output voltage and current with the example".

Thank you again for solving my problem.

Thanks,

Naga.