PIC18F2480 MICROCHIP [Microchip Technology], PIC18F2480 Datasheet - Page 26

• Manufacturer Part Number: PIC18F2480
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F2480/2580/4480/4580
TABLE 2-2:
DS39637A-page 24
Osc Type
Capacitor values are for design guidance only.
These capacitors were tested with the crystals 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
See the notes following this table for additional
information.
DD
Note 1: Higher capacitance increases the stability
XT
HS
LP
and temperature range for the application.
2: When operating below 3V V
3: Since each resonator/crystal has its own
4: Rs may be required to avoid overdriving
5: Always verify oscillator performance over
200 kHz
32 kHz
1 MHz
of the oscillator but also increases the
start-up time.
using certain ceramic resonators at any
voltage, it may be necessary to use the
HS mode or switch to a crystal oscillator.
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate
components.
crystals with low drive level specification.
the V
expected for the application.
200 kHz
Crystal
20 MHz
32 kHz
1 MHz
4 MHz
4 MHz
8 MHz
Freq
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
DD
Crystals Used:
and temperature range that is
Typical Capacitor Values
values
33 pF
15 pF
33 pF
27 pF
27 pF
22 pF
15 pF
C1
Tested:
20 MHz
4 MHz
8 MHz
of
DD
, or when
33 pF
15 pF
33 pF
27 pF
27 pF
22 pF
15 pF
external
C2
Preliminary
An external clock source may also be connected to the
OSC1 pin in the HS mode, as shown in Figure 2-2.
FIGURE 2-2:
2.3
The EC and ECIO Oscillator modes require an external
clock source to be connected to the OSC1 pin. There is
no oscillator start-up time required after a Power-on
Reset or after an exit from Sleep mode.
In the EC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic. Figure 2-3 shows the pin connections for the EC
Oscillator mode.
FIGURE 2-3:
The ECIO Oscillator mode functions like the EC mode,
except that the OSC2 pin becomes an additional
general purpose I/O pin. The I/O pin becomes bit 6 of
PORTA (RA6). Figure 2-4 shows the pin connections
for the ECIO Oscillator mode.
FIGURE 2-4:
Clock from
Ext. System
Clock from
Ext. System
Clock from
Ext. System
External Clock Input
F
Open
OSC
RA6
/4
EXTERNAL CLOCK
INPUT OPERATION
(HS OSCILLATOR
CONFIGURATION)
EXTERNAL CLOCK
INPUT OPERATION
(EC CONFIGURATION)
EXTERNAL CLOCK
INPUT OPERATION
(ECIO CONFIGURATION)
 2004 Microchip Technology Inc.
OSC1
OSC2
OSC1/CLKI
OSC2/CLKO
OSC1/CLKI
I/O (OSC2)
PIC18FXXXX
PIC18FXXXX
PIC18FXXXX
(HS Mode)