I2C address map for STUSB4500?

[jan1.1975]

Hi

Which registers can be read/write on the STUSB4500? What are the register addresses?

The datasheet only mentions the NVM parameters and their default values, how do you set them via i2c?

Thanks

JM

[TMark.8]

Hi All,

Two more issues with the STEVAL-ISC005V1:

1 I2C pullup resistors are 2k2 Ohm each. And they are killing I2C communication when the STEVAL-ISC005V1 is not powered. Unsoldering them fixed the problem. Possibly unsoldering SDA pullup resistor only could be enough.

2 There is a problem in the documentation: UM2398 (Rev01) page 18, Figure 22 : The resistors (R82, R83) order doesn't match the order in the board I have.

[Gregory Go.]

Hi,

Here are some comments.

• I2C pullup resistors are 2k2 Ohm each. And they are killing I2C communication when the STEVAL-ISC005V1 is not powered.

The STEVAL-ISC005V1 is not meant to be used without providing at least one source of power.

The pull-up resistors are required on both I2C pins.

On the STEVAL-ISC005V1 schematic, the pull-up voltage is 3.3V.

And the 3.3V is generated from 5V thanks to U83 voltage regulator.

So indeed, it is needed to provide 5V to have the I2C working properly.

There are 3 possible input sources for the 5V:

1/ 5V0: the 5V coming for the connector J81 (available if the STM32 Nucleo board is plugged in with a USB mini cable)

2/ Vsnk_5V : The 5V generated by U70, and coming from the Vbus voltage on USB-type-C connector (5V to 20V)

3/ uB_Vbus : The 5V coming from the on-board micro-USB connector.

• If you don't connect the USB-C connector, you still need power to power-on the USB-PD controller at 3.3V on VSYS pin, and thus to be able to program the chip.

So in this case again the 5V is required.

• There is a problem in the documentation: UM2398 (Rev01) page 18, Figure 22 : The resistors (R82, R83) order doesn't match the order in the board I have.

Thanks for your feedback. It seems the document doesn't contain the latest PCB layout picture.

[ABois]

Is there more details available about the I2C registers to read the state of the STUSB4500 ?

[Gregory Go.]

Hello,

The STUSB4500 register map is available in the STSW-STUSB003 Software Library package.

https://www.st.com/content/st_com/en/products/embedded-software/evaluation-tool-software/stsw-stusb003.html

You can also find it in attachment.

[JClar.0]

Hi Gregory,

I'm not sure if this document helps, to start with all of the contents of the 'description' columns are just the same register name with the word 'register' added on the end.

And then in the main datasheet stusb4500.pdf there are mentions of registers like SHIFT_VBUS_LL2, but in the docment you shared 'STUSB4500 Register Map - Public.pdf', these registers are not mentioned.

When can we expect a full datasheet for STUSB4500 the with all the information needed to reprogram it?

[Gregory Go.]

Hello,

Be careful that the STUSB4500 contains 2 kinds of memories:

- a bank of programmable registers (I2C register map)

- a Non-Voltage Memory (NVM), which contains the default device configuration at startup, and where the content is kept when there is no power.

The Table 16 of the datasheet ("STUSB4500 user-defined parameters and default settings") describes some parameters like SHIFT_VBUS_LL2.

However this table is not the I2C register map, but the NVM memory description.

So be careful of the confusion, because both memories are different.

The full register map is available in the STSW-STUSB003 package.

But even with the register map document, it is not easy to understand how to program the chip.

The best way to understand how to use the chip is to refer to the sample code in STSW-STUSB003 package.

There is also another sample code here:

https://github.com/usb-c/STUSB4500/tree/master/Firmware/Project/Src

Is there a specific feature that you want to implement which is not in the sample code ?

[TZeth]

just in case somebody is still looking for the register map, i have found a version of it on github: https://github.com/usb-c/STUSB4500/blob/master/Firmware/Doc/STUSB45%20Register%20Map%20-%20Public.pdf

[BRYAN SPEED]

We can also supply it quickly via online support - support home - via webform. on st.com