PIC18F-LF1XK50 MICROCHIP [Microchip Technology], PIC18F-LF1XK50 Datasheet - Page 15

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

2.0
2.1
The oscillator module has a variety of clock sources
and features that allow it to be used in a wide range of
applications, maximizing performance and minimizing
power consumption.
diagram of the oscillator module.
Key features of the oscillator module include:
• System Clock Selection
• Oscillator Start-up Timer
• System Clock Selection
• Clock Switching
• 4x Phase Lock Loop Frequency Multiplier
• CPU Clock Divider
• USB Operation
• Two-Speed Start-up Mode
• Fail-Safe Clock Monitoring
 2010 Microchip Technology Inc.
- Primary External Oscillator
- Secondary External Oscillator
- Internal Oscillator
- Low Speed
- Full Speed
OSCILLATOR MODULE
Overview
Figure 2-1
illustrates a block
Preliminary
2.2
The SCS bits of the OSCCON register select between
the following clock sources:
• Primary External Oscillator
• Secondary External Oscillator
• Internal Oscillator
TABLE 2-1:
The default state of the SCS bits sets the system clock
to be the oscillator defined by the FOSC bits of the
CONFIG1H Configuration register. The system clock
will always be defined by the FOSC bits until the SCS
bits are modified in software.
When the Internal Oscillator is selected as the system
clock, the IRCF bits of the OSCCON register and the
INTSRC bit of the OSCTUNE register will select either
the LFINTOSC or the HFINTOSC. The LFINTOSC is
selected when the IRCF<2:0> = 000 and the INTSRC
bit is clear. All other combinations of the IRCF bits and
the INTSRC bit will select the HFINTOSC as the
system clock.
2.3
The Primary External Oscillator’s mode of operation is
selected by setting the FOSC<3:0> bits of the
CONFIG1H Configuration register. The oscillator can
be set to the following modes:
• LP: Low-Power Crystal
• XT: Crystal/Ceramic Resonator
• HS: High-Speed Crystal Resonator
• RC: External RC Oscillator
• EC: External Clock
Additionally, the Primary External Oscillator may be
shut-down under firmware control to save power.
Configuration
SCS <1:0>
1x
01
00
(Default after Reset)
Note:
System Clock Selection
Primary External Oscillator
PIC18F/LF1XK50
The frequency of the system clock will be
referred to as F
document.
SYSTEM CLOCK SELECTION
Selection
System Clock
Internal Oscillator
Secondary External Oscillator
Oscillator defined by
FOSC<3:0>
OSC
DS41350E-page 15
throughout this