PIC12F519 Microchip Technology, PIC12F519 Datasheet - Page 39

• Manufacturer Part Number: PIC12F519
• Description: 8-Bit Flash Microcontroller
• Manufacturer: Microchip Technology

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8.2
8.2.1
The PIC12F519 device can be operated in up to four
different oscillator modes. The user can program using
the Configuration bits (FOSC<1:0>), to select one of
these modes:
• LP:
• XT:
• INTRC: Internal 4 MHz or 8 MHz Oscillator
• EXTRC: External Resistor/Capacitor
8.2.2
In XT or LP modes, a crystal or ceramic resonator is
connected to the (RB5)/OSC1/(CLKIN) and (RB4)/OSC2
pins to establish oscillation (Figure 8-1). The PIC12F519
oscillator designs require 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 or LP
modes, the device can have an external clock source
drive the (RB5)/OSC1/CLKIN pin (Figure 8-2). When the
part is used in this fashion, the output drive levels on the
OSC2 pin are very weak. This pin should be left open and
unloaded. Also when using this mode, the external clock
should observe the frequency limits for the clock mode
chosen (XT or LP).
FIGURE 8-1:
© 2007 Microchip Technology Inc.
Note 1:
Note 1: The user should verify that the device
C2
C1
2:
3:
Oscillator Configurations
(1)
(1)
Low-Power Crystal
Crystal/Resonator
CRYSTAL OSCILLATOR/CERAMIC
RESONATORS
OSCILLATOR TYPES
oscillator
expected. Adjusting the loading capacitor
values and/or the Oscillator mode may
be required.
See Capacitor Selection tables for
recommended values of C1 and C2.
A series resistor (RS) may be required for AT
strip cut crystals.
RF approx. value = 10 MΩ.
RS
XTAL
(2)
OSC1
OSC2
CRYSTAL OPERATION
(OR CERAMIC
RESONATOR)
(XT OR LP OSC
CONFIGURATION)
starts
RF
and
(3)
PIC12F519
performs
To internal
Sleep
logic
Preliminary
as
FIGURE 8-2:
TABLE 8-1:
TABLE 8-2:
Note 1:
Clock from
ext. system
Note:
Type
Type
Osc
Osc
XT
LP
XT
2:
Resonator
Resonator
For V
recommended.
Component values shown are for design
guidance only. Rs may be required 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 compo-
nents.
Component values shown are for design
guidance only. Since each resonator has
its own characteristics, the user should
consult the resonator manufacturer for
appropriate values of external compo-
nents.
32 kHz
4.0 MHz
200 kHz
1 MHz
4 MHz
Freq.
Freq.
Open
DD
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR –
PIC12F519
(1)
> 4.5V, C1 = C2 ≈ 30 pF is
EXTERNAL CLOCK INPUT
OPERATION (XT OR LP
OSC CONFIGURATION)
Cap. Range
Cap.Range
PIC12F519
47-68 pF
30 pF
15 pF
15 pF
15 pF
OSC2
OSC1
C1
C1
(2)
PIC12F519
DS41319A-page 37
Cap. Range
Cap. Range
47-68 pF
30 pF
15 pF
15 pF
15 pF
C2
C2