SYS_CLK goes away when unplugged

Spartan-3 USB 2.0 Modules
1

Hello,

I am currently trying to get the OK 3005 to work with an onborad USB2 hub chip. I am trying to run the hub off SYS_CLK4. The 3005 gets power from the board it is plugged into. I find that when I unplug the USB cable, usually the SYS_CLK4 signal goes away. Sometimes it doesn’t. Is there some way to prevent the PLL chip from dying, when the USB is unplugged?

Thanks,

Bill

2

Hi Bill–

Please email support. We have a firmware update that will keep the PLL active when the USB is detached.