In INTOSC mode, the OSC1/CLKIN and OSC2/CLKOUT pins are available for use as
a general purpose I/Os, provided that no external oscillator is connected. The function
of the OSC2/CLKOUT pin is determined by the CLKOUTEN
Configuration bit. When CLKOUTEN is set
(CLKOUTEN = 1
), the pin functions as a
general-purpose I/O. When CLKOUTEN is clear
(CLKOUTEN = 0
), the system instruction
clock (FOSC/4) is available as an output signal on the pin.