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PIC16LF1454 Datasheet, PDF (61/418 Pages) Microchip Technology – 14/20-Pin Flash, 8-Bit USB Microcontrollers with XLP Technology | |||
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5.2.1.4 3x PLL or 4x PLL
The oscillator module contains a PLL that can be used
with both external and internal clock sources to provide a
system clock source. By setting the SPLLMULT bit of the
OSCCON register, 3x PLL is selected. By clearing the
SPLLMULT bit of the OSCCON register, 4x PLL is
selected. The input frequency for the PLL must fall within
specifications. See the PLL Clock Timing Specifications in
Section 29.0 âElectrical Specificationsâ.
The PLL may be enabled for use by one of two methods:
1. Program the PLLEN bit in Configuration Words
to a â1â.
2. Write the SPLLEN bit in the OSCCON register to
a â1â. If the PLLEN bit in Configuration Words is
programmed to a â1â, then the value of SPLLEN
is ignored.
PLL
HFINTOSC
(MHz)
4x
8
3x
16, 8
ECH/HS
(MHz)
8 - 12
8 - 16
System
Clock (MHz)
32 - 48
24 - 48
5.2.1.5 Secondary Oscillator
The secondary oscillator is a separate crystal oscillator
that is associated with the Timer1 peripheral. It is opti-
mized for timekeeping operations with a 32.768 kHz
crystal connected between the SOSCO and SOSCI
device pins.
The secondary oscillator can be used as an alternate
system clock source and can be selected during
run-time using clock switching. Refer to Section 5.3
âCPU Clock Dividerâ for more information.
FIGURE 5-5:
QUARTZ CRYSTAL
OPERATION
(SECONDARY
OSCILLATOR)
PIC® MCU
SOSCI
C1
32.768 kHz
Quartz
Crystal
To Internal
Logic
C2
SOSCO
PIC16(L)F1454/5/9
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 Applications Notes:
⢠AN826, âCrystal Oscillator Basics and
Crystal Selection for rfPIC® and PIC®
Devicesâ (DS00826)
⢠AN849, âBasic PIC® Oscillator Designâ
(DS00849)
⢠AN943, âPractical PIC® Oscillator
Analysis and Designâ (DS00943)
⢠AN949, âMaking Your Oscillator Workâ
(DS00949)
⢠TB097, âInterfacing a Micro Crystal
MS1V-T1K 32.768 kHz Tuning Fork
Crystal to a PIC16F690/SSâ (DS91097)
⢠AN1288, âDesign Practices for
Low-Power External Oscillatorsâ
(DS01288)
ï£ 2012 Microchip Technology Inc.
Preliminary
DS41639A-page 61
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