Other Parts Discussed in Thread: TUSB542, TUSB522P
Hi Sir
We have use TUSB8041 solution in our project,and we found an issue during use.
The issue as belows:
The above figure is the System Block.
Host is pluggable.
1.1V and 3.3V power sources are always on.
Power of devices1~4 are always on.
When Host is unplugged, USB_VBUS is low.
When Host is plugged, USB_VBUS is high , HUBs start working, Devices1~4 will be enumerated.
The issue is:
After host is plugged in,some times, one of these devices(Device1~4) may fail to enumerate.
We have made the following attempts, but the issues have not been resolved.
Caes 1:
remove hub1,connect HOST directly to hub2,The situation of device enumeration failure still exists.
Case 2:
Using PWRCTL from hub1 instead of USB_VBUS of hub 2.The situation of device enumeration failure still exists.
Case 3:
Use USB_VBUS to Contrl the power of hub2.
when HOST is plugged,USB_VBUS is high,power of hub2 is on.
when HOST is unplugged,USB_VBUS is low,power of hub2 is off.
The situation of device enumeration failure still exists.
Could you teach me,why the USB enumeration of the device fails.
Thanks and best regards.