PIC18F-LF1XK50 MICROCHIP [Microchip Technology], PIC18F-LF1XK50 Datasheet - Page 19

• Manufacturer Part Number: PIC18F-LF1XK50
• Description: 20-Pin USB Flash Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

2.5
The internal oscillator module contains two independent
oscillators which are:
• LFINTOSC: Low-Frequency Internal Oscillator
• HFINTOSC: High-Frequency Internal Oscillator
When operating with either oscillator, OSC1 will be an
I/O and OSC2 will be either an I/O or CLKOUT. The
CLKOUT function is selected by the FOSC bits of the
CONFIG1H Configuration register. When OSC2 is
configured as CLKOUT, the frequency at the pin is the
frequency of the Internal Oscillator divided by 4.
2.5.1
The Low-Frequency Internal Oscillator (LFINTOSC) is
a 31 kHz internal clock source. The LFINTOSC
oscillator is the clock source for:
• Power-up Timer
• Watchdog Timer
• Fail-Safe Clock Monitor
The LFINTOSC is enabled when any of the following
conditions are true:
• Power-up Timer is enabled (PWRTEN = 0)
• Watchdog Timer is enabled (WDTEN = 1)
• Watchdog Timer is enabled by software
• Fail-Safe Clock Monitor is enabled (FCMEM = 1)
• SCS1 = 1 and IRCF<2:0> = 000 and INTSRC = 0
• FOSC<3:0> selects the internal oscillator as the
• IESO = 1 (Two-Speed Start-up) and
2.5.2
The High-Frequency Internal Oscillator (HFINTOSC) is
a precision oscillator that is factory-calibrated to
operate at 16 MHz. The output of the HFINTOSC
connects to a postscaler and a multiplexer (see
Figure
using the IRCF<2:0> bits of the OSCCON register. The
following
HFINTOSC:
• 16 MHZ
• 8 MHZ
• 4 MHZ
• 2 MHZ
• 1 MHZ (Default after Reset)
• 500 kHz
• 250 kHz
• 31 kHz
 2010 Microchip Technology Inc.
(WDTEN = 0 and SWDTEN = 1)
primary clock and IRCF<2:0> = 000 and
INTSRC = 0
IRCF<2:0> = 000 and INTSRC = 0
2-1). One of eight frequencies can be selected
Internal Oscillator
frequencies
LFINTOSC
HFINTOSC
are
available
from
Preliminary
the
The HFIOFS bit of the OSCCON register indicates
whether the HFINTOSC is stable.
The HFINTOSC is enabled if any of the following
conditions are true:
• SCS1 = 1 and IRCF<2:0>  000
• SCS1 = 1 and IRCF<2:0> = 000 and INTSRC = 1
• FOSC<3:0> selects the internal oscillator as the
• IESO = 1 (Two-Speed Start-up) and
• FCMEM = 1 (Fail Safe Clock Monitoring) and
primary clock and
Note 1: Selecting 31 kHz from the HFINTOSC
- IRCF<2:0>  000 or
- IRCF<2:0> = 000 and INTSRC = 1
- IRCF<2:0>  000 or
- IRCF<2:0> = 000 and INTSRC = 1
- IRCF<2:0>  000 or
- IRCF<2:0> = 000 and INTSRC = 1
2: Additional adjustments to the frequency
PIC18F/LF1XK50
oscillator requires IRCF<2:0> = 000 and
the INTSRC bit of the OSCTUNE register
to be set. If the INTSRC bit is clear, the
system
LFINTOSC.
of the HFINTOSC can made via the
OSCTUNE registers. See
for more details
clock
will
come
DS41350E-page 19
Register 2-3
from
the