My TUSB8044 can only be identified as a USB2.0 hub when connect to PC.
I design the circuit with reference to TUSB8044RGCEVM. There are differences:
1. I use upstream USB VBUS for all devices include TUSB8044 and a downstream IC (just a MCU)
2. I use DC-DC convert VBUS to 3.3V and 1.1V for TUSB8044
3. A EEPROM is connected to TUSB8044RGCEVM. SCL/SMBCLK and SDA/SMBDAT connect to a pull-up resistor But SMBUSz/SS_SUSPEND connected to a pull-down resistor. At first I didn't notice the error. (In datasheet, SMBUSz/SS_SUSPEND 1: I2C mode selected, 0: SMBus Mode Selected).
I am sure that the d+ d- SS_TX_UP and SS_RX_UP be connected correctly and the USB3.0 cable is OK.
It is noticeable, when I first connect the PCB to PC, no hub can be identified. After moving of the EEPROM IC and SCL/SMBCLK, SDA/SMBDAT SMBUSz/SS_SUSPEND 's resistor, it can be identified as a USB2.0 hub.
Is there any possible cause of this?
