PIC18F45J10 FAMILY
FIGURE 3-1:
CRYSTAL/CERAMIC
RESONATOROPERATION
(HS OR HSPLL
3.0
3.1
OSCILLATOR
CONFIGURATIONS
CONFIGURATION)
Oscillator Types
(1)
C1
The PIC18F45J10 family of devices can be operated in
five different oscillator modes:
OSC1
To
Internal
Logic
1. HS
High-Speed Crystal/Resonator
(3)
RF
XTAL
2. HSPLL High-Speed Crystal/Resonator
with Software PLL Control
Sleep
OSC2
3. EC
External Clock with FOSC/4 Output
(1)
(2)
RS
PIC18F45J10
C2
4. ECPLL External Clock with Software PLL
Control
Note 1: See Table 3-1 and Table 3-2 for initial values of
5. INTRC Internal 31 kHz Oscillator
C1 and C2.
Four of these are selected by the user by programming
the FOSC<2:0> 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: A series resistor (RS) may be required for AT
strip cut crystals.
3: RF varies with the oscillator mode chosen.
TABLE 3-1:
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
3.2
Crystal Oscillator/Ceramic
Resonators (HS Modes)
Typical Capacitor Values Used:
In HS or HSPLL Oscillator modes, a crystal or ceramic
resonator is connected to the OSC1 and OSC2 pins to
establish oscillation. Figure 3-1 shows the pin
connections.
Mode
Freq.
OSC1
OSC2
HS
8.0 MHz
16.0 MHz
27 pF
22 pF
27 pF
22 pF
The oscillator design requires the use of a parallel cut
crystal.
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.
Note:
Use of a series cut crystal may give a fre-
quency out of the crystal manufacturer’s
specifications.
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 3-2 for additional
information.
Resonators Used:
4.0 MHz
8.0 MHz
16.0 MHz
© 2009 Microchip Technology Inc.
DS39682E-page 27
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