SN8F2280 Series
USB 2.0 Full-Speed 8-Bit Micro-Controller
4.4 SYSTEM HIGH CLOCK
The system high clock is from the in circuit PLL. User must select the external oscillator 6MHz X’tal, 12MHz X’tal or
16MHz X’tal by the code option “Ext_OSC”, and all the three clock source will input to the on-chip PLL circuit. PLL will
output 12MHz to system clock (Fosc).
4.4.1 EXTERNAL HIGH CLOCK
External high clock includes three modules (Crystal/Ceramic and external clock signal). The start up time of crystal and
ceramic oscillator is different. The oscillator start-up time decides reset time length.
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