The device may be configured to use the internal oscillator block as the system clock by performing one of the following actions:
- Program the RSTOSC<2:0> bits in Configuration Words to
select the INTOSC clock as the default system clock upon a device Reset.
- Write the NOSC<2:0> bits to switch the system clock source to the internal
oscillator during run-time.
In INTOSC mode, OSC1/CLKIN is available for general purpose I/O. OSC2/CLKOUT is available for general purpose I/O or CLKOUT.
The function of the OSC2/CLKOUT pin is determined by the CLKOUTEN bit in Configuration Words.
The internal oscillator block has two independent oscillators that can produce two internal system clock sources.
- 1.The HFINTOSC (High-Frequency Internal Oscillator) is
factory-calibrated and operates from 1 to 64 MHz. The frequency of HFINTOSC can be
selected through the OSCFRQ Frequency Selection register, and fine-tuning can be done
via the OSCTUNE register.
- 2.The LFINTOSC (Low-Frequency Internal Oscillator) is
factory-calibrated and operates at 31 kHz.