STUSB1602 register definitions and I/O line control

[HardyFIN]

Hi, I need a comprehensive description of STUSB1602 registers to see if there's a possibility to control the I/O lines with them. I checked the git repository of firmwares and found something but I'd like to get a general description of the registers and what can be done with them. This seems to have been asked before without any clear replies and I can't find it in ST documentation either. So if you know any links that tell something about this, please post here.

Another question is: what is the reason a pull-up is required on the SPI lines?

The problem is, the MOSI line is sinking 200uA excess current due to the 10k pull-up when the device is in standby mode and this is not acceptable in this battery operated device. Is there a way to set the I/O pins in different states to avoid such current loss? There's a STM32G071 on the other end which currently has its SPI pins defined as no-pull.

If I remove the resistor this current doesn't flow and the problem disappears. But does the SPI bus work without it as it is clearly stated in the datasheet that it is required? 

Thanks in advance!

[NBALL · Accepted solution]

Hello

External pull up is mandatory. 
May be SPI pull ups could be supplied by a MCU GPIO so that when there is no connection, GPIO is grounded ?
connection is flagged thru I2C alert and there is time to restart SPI IPs.

Best regards

Nathalie

[TQuet.1]

Hello Nathalie. I also looking for STUSB1602 registers description and I can't found it on any place. The device is unusable without a good document. Where we can find this document?

[NBALL]

Hello

There is no I2C register description.

We do provide some software packages which include I2C and SPI management using STM32, upon request.

Best regards

Nathalie