2018-09-23 02:34 PM
Hi,
I am using STUSB4710AQTR. I build my board basing on reference design. Now I connected it to Microsoft Surface Go tablet. According datasheet this tablet support USB3.1 PD. However I even don't see any negotiation through CC lanes: only tablet send pulses with about 16Hz . Could you advice how to start debugging.
Thank you in advance
2018-10-02 06:04 PM
Hello,
Does the Microsoft Surface Go tablet at least work with the STEVAL-ISC004V1 evaluation board ?
First, the STUSB4710 must be powered-on (on Vdd) to work.
Then, once you connect the USB-C cable to your board (CC pin attached), STUSB4710 will start broadcasting its Power capabilities on the CC pin.
The STUSB4710 is a Power Source (DFP). It will only work in Power Delivery mode if connected to a Power Sink device (UFP), or a Dual Role Port application (DRP).
If you connect 2 Power Sources together, nothing will happen.
The NVM memory of the chip is pre-configured with default values during manufacturing (as seen in the datasheet). So it should be able to provide at least 5V (even if the other power profiles may not work if you don't configure the device properly first).
In any case, the STUSB47 will first monitor the input voltage before enabling it to VBUS lane. So if the chip doesn't measure 5V for instance, nothing power will be available on Vbus.
So make sure you USB-C input power (i.e the output of your power stage) is 5V at startup .
A way to debug the STUSB47 device, it is not use the Dashboard panel of the GUI, by connecting the I2C interface of STUSB4710 to the STM32 Nucleo board (NUCLEO-F072RB).
Like this you'll be able to see the current status of the chip, and understand what can be going wrong.
STSW-STUSB001 software GUI available here: