PIC16LF18854 Datasheet, PDF (113/668 Pages) Microchip Technology – C Compiler Optimized RISC Architecture

PIC16(L)F18856/76
6.2.1.4 4x PLL
The oscillator module contains a PLL that can be used
with external clock sources to provide a system clock
source. The input frequency for the PLL must fall within
specifications. See the PLL Clock Timing
Specifications in Table 37-9.
The PLL may be enabled for use by one of two
methods:
1. Program the RSTOSC bits in the Configuration
Word 1 to enable the EXTOSC with 4x PLL.
2. Write the NOSC bits in the OSCCON1 register
to enable the EXTOSC with 4x PLL.
6.2.1.5 Secondary Oscillator
The secondary oscillator is a separate oscillator block
that can be used as an alternate system clock source.
The secondary oscillator is optimized for 31 kHz, and
can be used with an external crystal oscillator con-
nected to the SOSCI and SOSCO device pins, or an
external clock source connected to the SOSCIN pin.
The secondary oscillator can be selected during
run-time using clock switching. Refer to Section 6.3
“Clock Switching” for more information.
FIGURE 6-5:
QUARTZ CRYSTAL
OPERATION
(SECONDARY
OSCILLATOR)
PIC^® MCU
SOSCI
C1
32.768 kHz
Quartz
Crystal
To Internal
Logic
C2
SOSCO
Note 1: Quartz crystal characteristics vary
according to type, package and
manufacturer. The user should consult the
manufacturer data sheets for specifications
and recommended application.
2: Always verify oscillator performance over
the VDD and temperature range that is
expected for the application.
3: For oscillator design assistance, reference
the following Microchip Application Notes:
• AN826, “Crystal Oscillator Basics and
Crystal Selection for rfPIC^® and PIC^®
Devices” (DS00826)
• AN849, “Basic PIC^® Oscillator Design”
(DS00849)
• AN943, “Practical PIC^® Oscillator
Analysis and Design” (DS00943)
• AN949, “Making Your Oscillator Work”
(DS00949)
• TB097, “Interfacing a Micro Crystal
MS1V-T1K 32.768 kHz Tuning Fork
Crystal to a PIC16F690/SS” (DS91097)
• AN1288, “Design Practices for
Low-Power External Oscillators”
(DS01288)
 2016 Microchip Technology Inc.
Preliminary
DS40001824A-page 113