- On the power-up initialization, disable SUSEN (POWER.0 - USB register)
- On bus reset handler, enable SUSEN

(*1) USB 2.0 Connect Timing ECN.pdf (included in zip file of USB 2.0 spec on USB.org)

Post-connect current timing
The Battery Charging spec allows devices to draw 100mA for 1 second after the connect event, regardless of what is happening on the bus.

The USB 2.0 spec currently requires devices to drop down to suspend current within 10ms of no bus activity, during both the attach debounce time (TATTDB) and during the reset time (TDRST). In practice, no devices do this. During USB compliance testing, suspend current is not tested until several seconds after the connect event.

The USB 2.0 spec would be modified such that a device is not required to drop down to the suspend current during the 1 second immediately following the connect event.

I hope that is the solution. If it is, I will post the fix to the forum.

Tsuneo, you may remember helping me debug it several years back. I noticed that SiLabs took most of our fixes we posted here and incorporated them into AN282SW. :-)

-Erik

P.S. They are still missing:

FLSCL |= 0x90; // set 48MHz for flash

After the clock init though.

2) Is your device bus-powered or self-powered?

3) When your firmware doesn't enable SUSEN (POWER.0) at all, (ie. if it always ignores Suspend), is it enumerated fine?

Tsuneo

1) Yes, on initial connection. Any version of Windows (W2K, XP, Vista) except Win7 (Win7 always works).
2) It is self-powered.
3) YES! However, is it safe to leave it like that? (I commented out the POWER = 0x01 in the USB Reset.)

After hacking for a few hours, it seems stable if I set POWER after a two second delay.

Thanks!
-Erik

P.S. After 9 days of 18 hour work days, finally some results! Thanks again.