PIC12C672 MICROCHIP [Microchip Technology], PIC12C672 Datasheet - Page 30

• Manufacturer Part Number: PIC12C672
• Description: 8-Pin, 8-Bit CMOS Microcontroller with EEPROM Data Memory
• Manufacturer: MICROCHIP [Microchip Technology]

PIC12CE5XX
8.2
8.2.1
The PIC12CE5XX can be operated in four different
oscillator
configuration bits (FOSC1:FOSC0) to select one of
these four modes:
• LP:
• XT:
• INTRC: Internal 4 MHz Oscillator
• EXTRC: External Resistor/Capacitor
8.2.2
In XT or LP modes, a crystal or ceramic resonator is
connected to the GP5/OSC1/CLKIN and GP4/OSC2
pins
PIC12CE5XX 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 or LP modes, the device
can have an external clock source drive the GP5/
OSC1/CLKIN pin (Figure 8-3).
FIGURE 8-2:
FIGURE 8-3:
DS40172A-page 30
Clock from
ext. system
Note 1: See Capacitor Selection tables for
to
2: A series resistor (RS) may be required for
3: RF varies with the crystal chosen
C2
C1
Oscillator Configurations
CRYSTAL OSCILLATOR / CERAMIC
RESONATORS
OSCILLATOR TYPES
(1)
(1)
recommended values of C1 and C2.
AT strip cut crystals.
(approx. value = 10 M ).
modes. The
Low Power Crystal
Crystal/Resonator
establish
Open
RS
XTAL
(2)
CRYSTAL OPERATION (OR
CERAMIC RESONATOR) (XT
OR LP OSC
CONFIGURATION)
EXTERNAL CLOCK INPUT
OPERATION (XT OR LP OSC
CONFIGURATION)
OSC2
OSC1
oscillation
user
OSC2
OSC1
RF
(3)
can
PIC12CE5XX
(Figure 8-2).
PIC12CE5XX
program
To internal
SLEEP
logic
The
Preliminary
two
TABLE 8-1:
TABLE 8-2:
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.
Note 1: For V
These values are for design guidance only. Rs may
be required in 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.
Type
Type
Osc
Osc
XT
LP
XT
recommended.
4.0 MHz
Resonator
Resonator
32 kHz
200 kHz
1 MHz
4 MHz
Freq
Freq
DD
CAPACITOR SELECTION
FOR CERAMIC RESONATORS
- PIC12CE5XX
CAPACITOR SELECTION
FOR CRYSTAL OSCILLATOR
- PIC12CE5XX
> 4.5V, C1 = C2
(1)
Cap. Range
Cap.Range
1997 Microchip Technology Inc.
47-68 pF
30 pF
15 pF
15 pF
15 pF
C1
C1
30 pF is
Cap. Range
Cap. Range
47-68 pF
15 pF
15 pF
30 pF
15 pF
C2
C2