Query about HX3

[chetang91]

hello, 

i am trying to implement  a USB HUB system using  ''CYUSB3324''. Is this possible to disable downstream USB port  by disconnecting only  vbus supply or do i need to cut-down data lines also (by separate hardware IC) to disable the port at downstream port ?

[Sananya_14 · Accepted solution]

Hello,

If you want the port to be disabled when there is an overcurrent condition, only VBUS removal is sufficient at the port and this should be taken care by the power switch using the PWREN signal from HX3 when OVRCURR is asserted. Without VBUS, the device on the port wont be able to complete enumeration as VBUS is needed for the terminations to be put up.

If you want to always disable the port in your application, you could do it using the hub disable option in the HX3 configuration. This can be done through Pin-Strapping, EEPROM or an I2C master depending on what the hub boot mode is set as. Please refer to Page 25 in the datasheet for more details.

Best Regards,
Sananya

[chetang91]

Query 1 : is this possible for me to disable individual port manually (by external IC like-  CPLD controller circuit ) whenever i need ?

[Sananya_14]

Hello,

Yes, you could use external logic to disable the ports but please note that the hub (and hence host) will not be notified of this so you would have to enable it manually as well for VBUS control.

Best Regards,

Sananya