JulsPower wrote:Hi
I wish to try V-USB for the first time
is it possible to run on the internal ATtiny861 if its supplied at 3.0V?
Read the datasheet again, it is pretty clear about this.
You can run the 861A from the "High-Frequency PLL Clock", just like the 85.
However: vUSB needs at least 12MHz, but the datasheet for the 861A says maximum save operating frequency @3V is 11.66MHz, just a bit outside of the save operating area. Furthermore, only the 12.5 and 16.5MHz modes of vUSB allow the use of the RC oscilator, which then would require at least 3.333V.
Finaly, if by 3.0V you meant two batteries - you get 1.5V only with brand new ones. When fully discharged, they have 0.8-1V each, and the maximum save operating frequency for the 861A @1.8V is only 4MHz.