Dear TI Team,
Last year I developed a PCB board using 3 pcs of TUSB4041I USB hub ICs and a 4-port USB-UART and a USB-I2C converter. I asked some questions on Jan 25, 2019 (TUSB4041I EEPROM Programming Tool) related to my project. The PCB became ready last spring and it worked very well with Windows 7, thanks for great support again. My problem started when I wanted to use it with Windows 10. I have tried it with different PC hardwares (Asus, Dell PP39L, Lenovo Y50-70 laptops, Intel NUC7i7BN and a desktop computer with Asus P8H77M motherboard). I found their behavior very different. The desktop recognised TUSB4041I hub ICs on my board, if I connected it to its USB2.0 ports, but not if I connected it to USB3.0 port. The Dell could also reciognise them, but the others not at all. All of mentioned computers were installed with 64-bit version of Windows 10 Pro. It seemed for me the newer the computer (and its USB driver), the worse its behavior with my board.
Alexey Tyutin sent a message into TUSB4041I Windows 10 topic on Jul 12, 2019 and he uploaded a schematic too. His problem was similar to mine and he found that removing a resistor from his board, the recognition problem disappears. Looking at his schematic, the removed resistor is the pull-up resistor of the clock signal of the configuration EEPROM. This removal means, that no high level of clock signal and TUSB4041I will not see the EEPROM, which means the configuration will be the default config. My board is also EEPROM configured, because I had to use the USB DP-DM polarity change feature in case of some downstream ports and I wanted to use some other features too. I have also tried Alexey's idea and my experience is the same: the recognition problem disappeared in all cases I have tried.
I think, the drivers for Windows 7 are written in correct way and as I found the board works flawlessly with EEPROM configuration too. My suspect is that Window 10 drivers don't handle EEPROM configuration well, because I cannot find any logical explanation to the behavior detailed above.
Please help me to solve this problem.
Thank you in advance.
Best regards,
Balazs Soregi