PIC18C242 MICROCHIP [Microchip Technology], PIC18C242 Datasheet - Page 15

• Manufacturer Part Number: PIC18C242
• Description: High-Performance Microcontrollers with 10-Bit A/D
• Manufacturer: MICROCHIP [Microchip Technology]

2.0
2.1
The PIC18CXX2 can be operated in eight different
oscillator modes. The user can program three configu-
ration bits (FOSC2, FOSC1, and FOSC0) to select one
of these eight modes:
1.
2.
3.
4.
5.
6.
7.
8.
2.2
In XT, LP, HS or HS-PLL 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. An external clock source may also
be connected to the OSC1 pin in these modes, as
shown in Figure 2-2.
The PIC18CXX2 oscillator design requires the use of a
parallel cut crystal.
7/99 Microchip Technology Inc.
Note:
LP
XT
HS
HS + PLL High Speed Crystal/Resonator with
RC
RCIO
EC
ECIO
OSCILLATOR
CONFIGURATIONS
Oscillator Types
Crystal Oscillator/Ceramic
Resonators
Use of a series cut crystal may give a fre-
quency out of the crystal manufacturers
specifications.
Low Power Crystal
Crystal/Resonator
High Speed Crystal/Resonator
PLL enabled
External Resistor/Capacitor
External Resistor/Capacitor with
I/O pin enabled
External Clock
External Clock with I/O pin enabled
Preliminary
FIGURE 2-1:
FIGURE 2-2:
Clock from
ext. system
Note 1: See Table 2-1 and Table 2-2 for recom-
Note 2: A series resistor (R
Note 3: R
C1
C2
(1)
(1)
mended values of C1 and C2.
for AT strip cut crystals.
XTAL
R
Open
F
S
(2)
varies with the crystal chosen.
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP
OSC CONFIGURATION)
OSC2
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR LP
OSC CONFIGURATION)
OSC1
PIC18CXX2
OSC1
OSC2
R
F
(3)
S
) may be required
PIC18CXXX
DS39026B-page 15
SLEEP
PIC18CXXX
To
internal
logic