PIC18F45J10 Datasheet, PDF (25/358 Pages) Microchip Technology – 28/40/44-Pin High-Performance RISC Microcontrollers with nanoWatt Technology

PIC18F45J10 FAMILY
2.0 OSCILLATOR
CONFIGURATIONS
2.1 Oscillator Types
The PIC18F45J10 family of devices can be operated in
five different oscillator modes:
1. HS
High-Speed Crystal/Resonator
2. HSPLL High-Speed Crystal/Resonator
with Software PLL Control
3. EC
External Clock with FOSC/4 Output
4. ECPLL External Clock with Software PLL
Control
5. INTRC Internal 31 kHz Oscillator
Four of these are selected by the user by programming
the FOSC2:FOSC0 configuration bits. The fifth mode
(INTRC) may be invoked under software control; it can
also be configured as the default mode on device
Resets.
2.2 Crystal Oscillator/Ceramic
Resonators (HS Modes)
In HS or HSPLL Oscillator modes, a crystal or ceramic
resonator is connected to the OSC1 and OSC2 pins to
establish oscillation. Figure 2-1 shows the pin
connections.
The oscillator design requires the use of a parallel cut
crystal.
Note:
Use of a series cut crystal may give a fre-
quency out of the crystal manufacturer’s
specifications.
FIGURE 2-1:
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS OR HSPLL
CONFIGURATION)
C1⁽¹⁾
OSC1
XTAL
RF⁽³⁾
To
Internal
Logic
C2⁽¹⁾
OSC2
RS⁽²⁾
Sleep
PIC18F45J10
Note 1: See Table 2-1 and Table 2-2 for initial values of
C1 and C2.
2: A series resistor (RS) may be required for AT
strip cut crystals.
3: RF varies with the oscillator mode chosen.
TABLE 2-1: CAPACITOR SELECTION FOR
CERAMIC RESONATORS
Typical Capacitor Values Used:
Mode
Freq.
OSC1
OSC2
HS
8.0 MHz
16.0 MHz
27 pF
22 pF
27 pF
22 pF
Capacitor values are for design guidance only.
These capacitors were tested with the resonators
listed below for basic start-up and operation. These
values are not optimized.
Different capacitor values may be required to produce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
VDD and temperature range for the application.
See the notes following Table 2-2 for additional
information.
Resonators Used:
4.0 MHz
8.0 MHz
16.0 MHz
© 2007 Microchip Technology Inc.
Preliminary
DS39682C-page 23