Quote Originally Posted by mister_e
Uh... my calculation were wrong... (1/12000000)*65536*2='round 10mSec. ARRGGH i don't have my stuff here to compare with mine... Darrel is on-line anyway
Steve, I'm trying to figure this out using math (gotta start sometime) and I'd like to know where you got the 12000000 from.

I read this link you posted in another thread:
http://ww1.microchip.com/downloads/e...Doc/41214a.pdf

And I got this formula from Tip #7:
Tosc x 4 x 65536 x prescaler

I am using a 48MHz crystal so I get this:
(1/48000000) x 4 x 65536 x 2 = 0.0109226 (repeating)

D'uh, ok, I see it now, 48 / 4 = 12, that's where you got your value. So, as you said, that interval rounds up to just over 10ms, that 'should' work.

I'm sure it has something to do with the interrupt occurring right in the middle of USB processing and interfering with the connection. I don't see what else it can be; the interrupt seems fine, the USB works.

Robert