PIC16CR56AT-LPP View Datasheet(PDF) - Microchip Technology
Part Name
Description
Manufacturer
PIC16CR56AT-LPP Datasheet PDF : 192 Pages
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4.0 OSCILLATOR
CONFIGURATIONS
4.1 Oscillator Types
PIC16C5Xs can be operated in four different oscillator
modes. The user can program two configuration bits
(FOSC1:FOSC0) to select one of these four modes:
1. LP:
2. XT:
3. HS:
4. RC:
Low Power Crystal
Crystal/Resonator
High Speed Crystal/Resonator
Resistor/Capacitor
Note: Not all oscillator selections available for all
parts. See Section 9.1.
4.2 Crystal Oscillator/Ceramic
Resonators
In XT, LP or HS modes, a crystal or ceramic resonator
is connected to the OSC1/CLKIN and OSC2/CLKOUT
pins to establish oscillation (Figure 4-1). The
PIC16C5X oscillator design requires the use of a paral-
lel cut crystal. Use of a series cut crystal may give a fre-
quency out of the crystal manufacturers specifications.
When in XT, LP or HS modes, the device can have an
external clock source drive the OSC1/CLKIN pin
(Figure 4-2).
FIGURE 4-1:
C1(1)
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP OSC
CONFIGURATION)
OSC1
PIC16C5X
XTAL
OSC2
RS(2)
C2(1)
RF(3)
SLEEP
To internal
logic
Note 1: See Capacitor Selection tables for
recommended values of C1 and C2.
2: A series resistor (RS) may be required
for AT strip cut crystals.
3: RF varies with the Oscillator mode cho-
sen (approx. value = 10 M).
PIC16C5X
FIGURE 4-2:
Clock from
ext. system
Open
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR
LP OSC
CONFIGURATION)
OSC1
PIC16C5X
OSC2
TABLE 4-1:
CAPACITOR SELECTION FOR
CERAMIC RESONATORS -
PIC16C5X, PIC16CR5X
Osc Resonator Cap. Range Cap. Range
Type
Freq
C1
C2
XT
455 kHz 68-100 pF 68-100 pF
2.0 MHz 15-33 pF
15-33 pF
4.0 MHz 10-22 pF
10-22 pF
HS
8.0 MHz
10-22 pF
16.0 MHz
10 pF
10-22 pF
10 pF
These values are for design guidance only. Since
each resonator has its own characteristics, the user
should consult the resonator manufacturer for
appropriate values of external components.
TABLE 4-2:
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR -
PIC16C5X, PIC16CR5X
Osc
Type
Crystal
Freq
Cap.Range Cap. Range
C1
C2
LP
32 kHz(1)
15 pF
15 pF
XT
100 kHz 15-30 pF 200-300 pF
200 kHz 15-30 pF 100-200 pF
455 kHz 15-30 pF 15-100 pF
1 MHz
15-30 pF
15-30 pF
2 MHz
15 pF
15 pF
4 MHz
15 pF
15 pF
HS
4 MHz
8 MHz
20 MHz
15 pF
15 pF
15 pF
15 pF
15 pF
15 pF
Note 1: For VDD > 4.5V, C1 = C2 30 pF is
recommended.
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 manufacturer for
appropriate values of external components.
Note:
If you change from this device to another
device, please verify oscillator characteris-
tics in your application.
1997-2013 Microchip Technology Inc.
Preliminary
DS30453E-page 15
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