PIC18F87J90 Datasheet, PDF (35/450 Pages) Microchip Technology – 64/80-Pin, High-Performance Microcontrollers with LCD Driver and nanoWatt Technology

PIC18F87J90 FAMILY
3.0 OSCILLATOR
CONFIGURATIONS
3.1 Oscillator Types
The PIC18F87J90 family of devices can be operated in
eight different oscillator modes:
1. ECPLL
2. EC
3. HSPLL
OSC1/OSC2 as primary; ECPLL
oscillator with PLL enabled, CLKO on
RA6
OSC1/OSC2 as primary; external
clock with FOSC/4 output
OSC1/OSC2 as primary; high-speed
crystal/resonator with software PLL
control
4. HS
OSC1/OSC2 as primary; high-speed
crystal/resonator
5. INTPLL1 Internal oscillator block with software
PLL control, FOSC/4 output on RA6
and I/O on RA7
6. INTIO1 Internal oscillator block with FOSC/4
output on RA6 and I/O on RA7
7. INTPLL2 Internal oscillator block with software
PLL control and I/O on RA6 and RA7
8. INTIO2 Internal oscillator block with I/O on
RA6 and RA7
All of these modes are selected by the user by
programming the FOSC<2:0> Configuration bits.
In addition, PIC18F87J90 family devices can switch
between different clock sources, either under software
control or automatically under certain conditions. This
allows for additional power savings by managing
device clock speed in real time without resetting the
application.
The clock sources for the PIC18F87J90 family of
devices are shown in Figure 3-1.
FIGURE 3-1:
PIC18F87J90 FAMILY CLOCK DIAGRAM
OSC2
OSC1
T1OSO
T1OSI
Primary Oscillator
Sleep
OSCTUNE<6>
Secondary Oscillator
T1OSCEN
Enable
Oscillator
OSCCON<6:4>
Internal
Oscillator
Block
8 MHz
Source
8 MHz
(INTOSC)
INTRC
Source
31 kHz (INTRC)
HS, EC
4 x PLL
HSPLL, ECPLL, INTPLL
T1OSC
Peripherals
OSCCON<6:4>
8 MHz
111
4 MHz
110
2 MHz
101
1 MHz
100
500 kHz
011
250 kHz
010
125 kHz
001
1 31 kHz
000
0
OSCTUNE<7>
Internal Oscillator
CPU
Clock
Control
IDLEN
FOSC<2:0> OSCCON<1:0>
Clock Source Option
for Other Modules
WDT, PWRT, FSCM
and Two-Speed Start-up
 2010 Microchip Technology Inc.
DS39933D-page 35