PIC16F62X
14.2
Oscillator Configurations
TABLE 14-1: CAPACITOR SELECTION FOR
CERAMIC RESONATORS
14.2.1
OSCILLATOR TYPES
Ranges Characterized:
The PIC16F62X can be operated in eight different
oscillator options. The user can program three
configuration bits (FOSC2 thru FOSC0) to select one of
these eight modes:
Mode
Freq
OSC1(C1)
OSC2(C2)
455 kHz
2.0 MHz
4.0 MHz
22 - 100 pF
15 - 68 pF
15 - 68 pF
22 - 100 pF
15 - 68 pF
15 - 68 pF
XT
• LP
Low Power Crystal
8.0 MHz
16.0 MHz
10 - 68 pF
10 - 22 pF
10 - 68 pF
10 - 22 pF
• XT
Crystal/Resonator
HS
• HS
• ER
• INTRC
• EC
High Speed Crystal/Resonator
External Resistor (2 modes)
Internal Resistor/Capacitor (2 modes)
External Clock In
Higher capacitance increases the stability of the oscillator
but also increases the start-up time. These values are for
design guidance only. Since each resonator has its own
characteristics, the user should consult the resonator man-
ufacturer for appropriate values of external components.
14.2.2 CRYSTAL OSCILLATOR / CERAMIC
RESONATORS
TABLE 14-2: CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
In XT, LP or HS modes a crystal or ceramic resonator
is connected to the OSC1 and OSC2 pins to establish
oscillation (Figure 14-2). The PIC16F62X 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 OSC1 pin (Figure 14-3).
Mode
Freq
OSC1(C1)
OSC2(C2)
LP
32 kHz
200 kHz
68 - 100 pF
15 - 30 pF
68 - 100 pF
15 - 30 pF
XT
HS
100 kHz
2 MHz
4 MHz
68 - 150 pF
15 - 30 pF
15 - 30 pF
150 - 200 pF
15 - 30 pF
15 - 30 pF
8 MHz
10 MHz
20 MHz
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF
FIGURE 14-2: CRYSTAL OPERATION
(OR CERAMIC RESONATOR)
(HS, XT OR LP OSC
Higher capacitance increases the stability of the oscillator
but also increases the start-up time. These values are for
design guidance only. Rs may be required in HS mode as
well as XT mode to avoid overdriving crystals with low drive
level specification. Since each crystal has its own
characteristics, the user should consult the crystal manu-
facturer for appropriate values of external components.
CONFIGURATION)
OSC1
To internal logic
C1
XTAL
RS
SLEEP
RF
OSC2
see Note
C2
PIC16F62X
See Table 14-1 and Table 14-2 for recommended
values of C1 and C2.
Note: A series resistor may be required for
AT strip cut crystals.
FIGURE 14-3: EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR LP
OSC CONFIGURATION)
Clock from
ext. system
OSC1
PIC16F62X
OSC2
Open
1999 Microchip Technology Inc.
Preliminary
DS40300B-page 97
MICROCHIP [ MICROCHIP ]
