Microchip Technology IC PIC MCU PIC18F65J15-I/PT TQFP-64 MCP PIC18F65J15-I/PT Data Sheet

© 2009 Microchip Technology Inc.

DS39663F-page 31

The PIC18F87J10 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 F

OSC

/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 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.

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. 
The oscillator design requires the use of a parallel cut
crystal.    

Use of a series cut crystal may give a fre-
quency out of the crystal manufacturer’s
specifications.

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
V

DD

 and temperature range for the application.

See the notes following Table 3-2 for additional
information.

4.0 MHz
8.0 MHz

16.0 MHz

Note 1: See Table 3-1 and Table 3-2 for initial values of

C1 and C2.

2: A series resistor (R

S

) may be required for AT

strip cut crystals.

3: R

F

 varies with the oscillator mode chosen.

C1

C2

XTAL

OSC2

OSC1

R

F

Sleep

To

Logic

R

S(2)

Internal