How to determine the actual clock frequency for Full-speed USB IC?
SN8P221X actual Fosc is 2 times of external crystal frequency;
SN8F225X and SN8F228X clock frequency relationship with the Code Option High_SCK options are as follows:
Code Option High_SCK options actual clock frequency 6M _X' tal 2 times of external crystal frequency 12M_X’tal external crystal frequency 16M_X’tal 3/4 of external crystal frequency Note that in full-speed USB mode, all the actual clock of full-speed IC series must work under 12M frequency.