PIC16C926 Microchip Technology Inc., PIC16C926 Datasheet - Page 101

• Manufacturer Part Number: PIC16C926
• Description: 64/68-pin Cmos Microcontrollers With Lcd Driver
• Manufacturer: Microchip Technology Inc.

12.2
12.2.1
The PIC16CXXX can be operated in four different oscil-
lator modes. The user can program two configuration
bits (FOSC1 and FOSC0) to select one of these four
modes:
• LP
• XT
• HS
• RC
12.2.2
In XT, LP, or HS modes a crystal or ceramic resonator
is connected to the OSC1/CLKIN and OSC2/CLKOUT
pins to establish
PIC16CXXX oscillator design requires the use of a par-
allel cut crystal. Use of a series cut crystal may give a
frequency out of the crystal manufacturers specifica-
tions. When in XT, LP, or HS modes, the device can
have
OSC1/CLKIN pin (Figure 12-2).
FIGURE 12-1:
FIGURE 12-2:
See Table 12-1 and Table 12-2 for recommended values
of C1 and C2.
Note 1: A series resistor may be required for AT strip
2001 Microchip Technology Inc.
Clock from
Ext. System
an
Oscillator Configurations
C1
C2
cut crystals.
Low Power Crystal
Crystal/Resonator
High Speed Crystal/Resonator
Resistor/Capacitor
CRYSTAL OSCILLATOR/CERAMIC
RESONATORS
external
OSCILLATOR TYPES
(Note 1)
Open
XTAL
RS
OSC1
OSC2
oscillation (Figure 12-1).
CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP
OSC CONFIGURATION)
EXTERNAL CLOCK INPUT
OPERATION (HS, XT OR
LP OSC
CONFIGURATION)
clock
OSC1
OSC2
R
source
F
PIC16CXXX
PIC16CXXX
SLEEP
to
To Internal
Logic
drive
The
Preliminary
the
TABLE 12-1:
TABLE 12-2:
These values are for design guidance only.
See notes following Table 12-2.
These values are for design guidance only.
See notes following this table.
Osc Type
Mode
Note 1: Recommended ranges of C1 and C2 are
HS
XT
HS
LP
XT
2: Higher capacitance increases the stability
3: Since each resonator/crystal has its own
4: Rs may be required in HS mode, as well
depicted in Table 12-1.
of the oscillator, but also increases the
start-up time.
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate values of external compo-
nents.
as XT mode, to avoid overdriving crystals
with low drive level specification.
200 kHz
200 kHz
455 kHz
2.0 MHz
4.0 MHz
8.0 MHz
Crystal
32 kHz
1 MHz
4 MHz
4 MHz
8 MHz
PIC16C925/926
Freq.
Freq.
CERAMIC RESONATORS
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
Ranges Tested:
Cap. Range
68 - 100 pF
47-68 pF
15-33 pF
15 - 68 pF
15 - 68 pF
10 - 68 pF
33 pF
15 pF
15 pF
15 pF
15 pF
C1
C1
DS39544A-page 99
68 - 100 pF
15 - 68 pF
15 - 68 pF
10 - 68 pF
47-68 pF
15-33 pF
Range
33 pF
15 pF
15 pF
15 pF
15 pF
Cap.
C2
C2