PIC16C717-I/SS View Datasheet(PDF) - Microchip Technology
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PIC16C717-I/SS Datasheet PDF : 200 Pages
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FIGURE 12-2: CRYSTAL/CERAMIC
RESONATOR OPERATION
(HS, XT OR LP
OSC CONFIGURATION)
C1(1)
OSC1
XTAL
C2(1)
OSC2
RS(2)
RF(3)
To
internal
logic
SLEEP
PIC16C717/770/771
Note1:
2:
3:
See Table 12-1 and Table 12-2 for recom-
mended values of C1 and C2.
A series resistor (RS) may be required for
AT strip cut crystals.
RF varies with the crystal chosen.
TABLE 12-1: CERAMIC RESONATORS
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.
All resonators used did not have built-in capacitors.
TABLE 12-2: CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
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.
Note 1: Since each resonator/crystal has its own
characteristics, the user should consult the
resonator/crystal manufacturer for appropri-
ate values of external components.
2: Higher capacitance increases the stability
of oscillator but also increases the start-up
time.
PIC16C717/770/771
12.2.3 EC MODE
In applications where the clock source is external, the
PIC16C717/770/771 should be programmed to select
the EC (External Clock) mode. In this mode, the RA6/
OSC2/CLKOUT pin is available as an I/O pin. See
Figure 12-3 for illustration.
FIGURE 12-3: EXTERNAL CLOCK INPUT
OPERATION (EC OSC
CONFIGURATION)
Clock from
ext. system
I/O
OSC1
PIC16C717/770/771
RA6
© 1999 Microchip Technology Inc.
Advanced Information
DS41120A-page 127
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