RFPIC12F675H Microchip Technology Inc., RFPIC12F675H Datasheet - Page 59

• Manufacturer Part Number: RFPIC12F675H
• Description: 20-pin Flash-based 8-bit Cmos Microcontroller With Uhf Ask/fsk Transmitter
• Manufacturer: Microchip Technology Inc.

10.2
10.2.1
The rfPIC12F675 can be operated in eight different
Oscillator Option modes. The user can program three
configuration bits (FOSC2 through FOSC0) to select
one of these eight modes:
• LP
• XT
• HS
• RC
• INTOSC Internal Oscillator (2 modes)
• EC
10.2.2
In XT, LP or HS modes a crystal or ceramic resonator
is connected to the OSC1 and OSC2 pins to establish
oscillation
oscillator design requires the use of a parallel cut
crystal. Use of a series cut crystal may yield a
frequency outside 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 (see Figure 10-2).
FIGURE 10-1:
 2003 Microchip Technology Inc.
Note
Note:
C1
C2
1:
2:
3:
Oscillator Configurations
(1)
(1)
Low Power Crystal
Crystal/Resonator
High Speed Crystal/Resonator
External Resistor/Capacitor (2 modes)
External Clock In
Additional information on oscillator config-
urations is available in the PICmicro
Mid-Range
(DS33023)
OSCILLATOR TYPES
CRYSTAL OSCILLATOR / CERAMIC
RESONATORS
See Table 10-1 and Table 10-2 for recommended
values of C1 and C2.
A series resistor may be required for AT strip cut
crystals.
RF varies with the Oscillator mode selected
(Approx. value = 10 MΩ).
(see
RS
XTAL
(2)
OSC1
OSC2
Figure 10-1).
CRYSTAL OPERATION (OR
CERAMIC RESONATOR)
HS, XT OR LP OSC
CONFIGURATION
RF
Reference
(3)
PIC12F629/675
The
SLEEP
To Internal
Logic
rfPIC12F675
Manual,
Preliminary
TM
FIGURE 10-2:
TABLE 10-1:
TABLE 10-2:
Note 1: Higher capacitance increases the stability
Note 1: Higher capacitance increases the stability
Mode
Clock from
External System
Mode
HS
XT
XT
HS
Note 1: Functions as GP4 in EC Osc mode.
LP
Open
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 manufacturer for
appropriate values of external
components.
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 manufacturer for
appropriate values of external
components.
16.0 MHz
2.0 MHz
4.0 MHz
8.0 MHz
455 kHz
100 kHz
10 MHz
20 MHz
32 kHz
Freq
2 MHz
4 MHz
8 MHz
Freq
Ranges Characterized:
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
rfPIC12F675
EXTERNAL CLOCK INPUT
OPERATION (HS, XT, EC,
OR LP OSC
CONFIGURATION)
68 - 100 pF
OSC1(C1)
68 - 100 pF
68 - 150 pF
15 - 68 pF
15 - 68 pF
10 - 68 pF
10 - 22 pF
OSC1(C1)
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF
OSC1
OSC2
PIC12F629/675
(1)
DS70091A-page 57
150 - 200 pF
68 - 100 pF
68 - 100 pF
OSC2(C2)
15 - 68 pF
15 - 68 pF
10 - 68 pF
10 - 22 pF
OSC2(C2)
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF
15 - 30 pF