Objective Development Forums

I had the same issue as you, and was using the SOF hook to capture the value of a timer and clear it. I skipped the extra run through the hook routine by looking for a low timer value and jumping past the rest of the code in the routine if the value was too low. Hope that helps (maybe not you, but s...

I was able to trace this back to using the pin-change interrupt instead of INT0. The interrupt is executed on any change to the pin, not just on the rising edge of the signal that is normally used, and so two interrupts are generated by the SOF pulse.

I'm trying to get the alternate oscialltor calibration routine using the timer working in my application, and was running into some weird issues. I found that the USB_SOF_HOOK was being executed twice per frame, a couple microseconds apart when there is no data, or separated further if there is data...

This thread helped me understand why there wasn't a V-USB based bootloader for the ATtiny85 when I went looking for one. I did figure out how to work around the issues with the ATtiny architecture and updated Christian's USBaspLoader project to have ATtiny85 support. It's still a work in progress, t...