PIC16C432-I View Datasheet(PDF) - Microchip Technology
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PIC16C432-I Datasheet PDF : 106 Pages
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9.2 Oscillator Configurations
9.2.1 OSCILLATOR TYPES
The PIC16C432 can be operated in four different
oscillator options. 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
9.2.2
CRYSTAL OSCILLATOR/CERAMIC
RESONATORS
In XT, LP or HS modes, a crystal or ceramic resonator
is connected to the OSC1 and OSC2 pins to establish
oscillation (Figure 9-1). The PIC16C432 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 9-2).
FIGURE 9-1:
CRYSTAL OPERATION
(OR CERAMIC
RESONATOR) (HS, XT OR
LP OSC
CONFIGURATION)
OSC1
C1
XTAL
OSC2
RS
C2 Note 2
To Internal Logic
RF
SLEEP
PIC16C432
Note 1: See Table 9-1 and Table 9-2 for recom-
mended values of C1 and C2.
2: A series resistor may be required for AT strip
cut crystals.
FIGURE 9-2:
Clock from
ext. system
Open
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR
LP OSC
CONFIGURATION)
OSC1
PIC16C432
OSC2
PIC16C432
TABLE 9-1: CERAMIC RESONATORS,
PIC16C432
Ranges Tested:
Mode
Freq
OSC1
OSC2
XT
455 kHz 68 - 100 pF 68 - 100 pF
2.0 MHz 15 - 68 pF 15 - 68 pF
4.0 MHz 15 - 68 pF 15 - 68 pF
HS
8.0 MHz 10 - 68 pF 10 - 68 pF
16.0 MHz 10 - 22 pF 10 - 22 pF
These values are for design guidance only. See
notes at bottom of page.
TABLE 9-2:
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR,
PIC16C432
Osc Type
Crystal
Freq
Cap. Range
Cap.
C1
Range C2
LP
32 kHz 33 pF
33 pF
200 kHz 15 pF
15 pF
XT
200 kHz 47-68 pF
47-68 pF
1 MHz 15 pF
15 pF
4 MHz 15 pF
15 pF
HS
4 MHz 15 pF
15 pF
8 MHz 15-33 pF
15-33 pF
20 MHz 15-33 pF
15-33 pF
These values are for design guidance only. See
notes at bottom of page.
Note 1: Recommended values of C1 and C2 are
indentical to the ranges tested table.
2: Higher capacitance increases the stability
of oscillator, but also increases the start-
up time.
3: Since each resonator/crystal has its own
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate values of external compo-
nents.
4: Rs may be required in HS mode, as well
as XT mode, to avoid over driving crystals
with low drive level specification.
2000-2013 Microchip Technology Inc.
Preliminary
DS41140C-page 45
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