I am hoping to understand whether or not this STUSB4500 PD controller on this evaluation board will default to a 5V sink level if it attaches to a standard USB-A port that does not communicate over the CC lines. I have tried this with a USB-C PD source and it negotiates a 15V contract and works fine. One of my requirements however is to get it to work with a standard PC USB-A port. When I connect that into the board using a USB A to Micro USB cable with a Micro to USB-C converter the VBUS powers, but the controller never turns on the FET to pass the VBUS out to the VSINK output. My MCU power supply operates off of the VBUS input as it has a wide input span up to 25V, but I never see it turn on the FET to pass the 5V power out to the VSINK output. Does it not turn this on because there is no communication on the CC lines. Should it not default to a 5V contract? Can I possibly get my software engineer to set up 5V @ 500mA as a default contract over the I2C bus by setting some internal registers in a case like this?
