We are using a Cypress FX2 (same as the OSR USB FX-2 Learning Kit) and
would like to implement remote wakeup capability where the PC host can
wakeup the USB device remotely. Currently, our FX2 will automatically
go idle after a period of inactivity. It can wake itself up
automatically, it renumerates and the host connects to it.
Could you give me some hints on how to implement the ability for the
host to wakeup the device remotely?
Our first attempt at implementing this was to use registry entry
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\usb]
“EnSoftRetry”=dword:00000001. This registry entry allowed the USB
connection to remain open wile the FX2 was idle. The host could send
any USB command to the FX2, the FX2 would periodically wake itself up
and upon seeing a USB command, would keep itself awake. Although this
registry entry provided the remote device wakeup capability we’re
looking for, it also caused side effects such as random Unknown Device
errors, random disconnects and other erratic USB behavior.
If the learning kit does this, I’d gladly get one and try it out. From
what I’ve read so far, the kit will wake the host but not the other
way around.
Thanks for any suggestions you can offer.
-Jim