16-Bit Oscillator System: CPU Clocking Scheme

The system clock source (FOSC) may be selected from one of 5 sources:

  • Primary Oscillator (POSC) on the OSC1 and OSC2 pins
  • Internal Phase-Locked Loop (PLL)
  • Internal Fast RC Oscillator (FRC)
  • Internal Low-Power RC Oscillator (LPRC)
  • Secondary Oscillator (SOSC) on the SOSCI and SOSCO pins

This clock is then divided by 2 to produce the internal peripheral clock (FP) and core CPU instruction cycle clock, FCY as shown:


FCY may optionally be further divided down using DOZE mode settings, which enables power savings while continuing to run the peripherals at FOSC / 2.

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