11.2.1 External Clock Sources

An external clock source can be used as the device system clock by performing the following actions:
  • Program the RSTOSC Configuration bits to select the external clock source (RSTOSC = 111)
  • Program the FEXTOSC Configuration bits to select the appropriate External Clock (EC) mode:
    • ECH mode for oscillators operating at or above 16 MHz (FEXTOSC = 11)
    • ECL mode for oscillator operating below 16 MHz (FEXTOSC = 01)