PIC16CE624T-04SS View Datasheet(PDF) - Microchip Technology
Part Name
Description
Manufacturer
PIC16CE624T-04SS Datasheet PDF : 113 Pages
| |||
10.2 Oscillator Configurations
10.2.1 OSCILLATOR TYPES
The PIC16CE62X 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
• XT
• HS
• RC
Low Power Crystal
Crystal/Resonator
High Speed Crystal/Resonator
Resistor/Capacitor
10.2.2 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 10-1). The PIC16CE62X 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 10-2).
FIGURE 10-1: CRYSTAL OPERATION
(OR CERAMIC RESONATOR)
(HS, XT OR LP OSC
CONFIGURATION)
OSC1
C1
XTAL
OSC2
RS
C2 see Note
To Internal Logic
RF
SLEEP
PIC16CE62X
See Table 10-1 and Table 10-2 for recommended values
of C1 and C2.
Note:
A series resistor may be required for AT
strip cut crystals.
FIGURE 10-2: EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR LP
OSC CONFIGURATION)
Clock From
ext. system
Open
OSC1
PIC16CE62X
OSC2
PIC16CE62X
TABLE 10-1: CERAMIC RESONATORS,
PIC16CE62X
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 10-2: CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR,
PIC16CE62X
Osc Type
Crystal
Freq
Cap. Range Cap. Range
C1
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.
1. Recommended values of C1 and C2 are identical 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 characteris-
tics, the user should consult the resonator/crystal
manufacturer for appropriate values of external com-
ponents.
4. Rs may be required in HS mode, as well as XT mode,
to avoid overdriving crystals with low drive level spec-
ification.
© 1999 Microchip Technology Inc.
DS40182C-page 51
Share Link: 