
PIC16F8X
1998 Microchip Technology Inc.
DS30430C-page 39
FIGURE 8-2:
CONFIGURATION WORD - PIC16F83 AND PIC16F84
8.2
Oscillator Configurations
8.2.1
OSCILLATOR TYPES
The PIC16F8X can be operated in four different
oscillator
modes.
The
user
can
program
two
configuration bits (FOSC1 and FOSC0) to select one of
these four modes:
LP
Low Power Crystal
XT
Crystal/Resonator
HS
High Speed Crystal/Resonator
RC
Resistor/Capacitor
8.2.2
CRYSTAL OSCILLATOR / CERAMIC
RESONATORS
In XT, LP or HS modes a crystal or ceramic resonator
is connected to the OSC1/CLKIN and OSC2/CLKOUT
FIGURE 8-3:
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP OSC
CONFIGURATION)
The PIC16F8X oscillator design requires the use of a
parallel cut crystal. Use of a series cut crystal may give
a
frequency
out
of
the
crystal
manufacturers
specifications. When in XT, LP or HS modes, the device
can have an external clock source to drive the
R/P-u
R/P-u R/P-u R/P-u R/P-u R/P-u
R/P-u
CP
PWRTE WDTE FOSC1 FOSC0
bit13
bit0
R
= Readable bit
P
= Programmable bit
- n = Value at POR reset
u = unchanged
bit 13:4 CP: Code Protection bit
1 = Code protection off
0 = All memory is code protected
bit 3
PWRTE: Power-up Timer Enable bit
1 = Power-up timer is disabled
0 = Power-up timer is enabled
bit 2
WDTE: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled
bit 1:0
FOSC1:FOSC0: Oscillator Selection bits
11
= RC oscillator
10
= HS oscillator
01
= XT oscillator
00
= LP oscillator
Note1:
C1 and C2.
2:
A series resistor (RS) may be required for
AT strip cut crystals.
3:
RF varies with the crystal chosen.
C1(1)
C2(1)
XTAL
OSC2
OSC1
RF(3)
SLEEP
To
logic
PIC16FXX
RS(2)
internal