PIC16LC715-20I/SO 查看數據表（PDF） - Microchip Technology

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PIC16LC715-20I/SO

8-Bit CMOS Microcontrollers with A/D Converter

Microchip Technology 

8.2 Oscillator Configurations

8.2.1 OSCILLATOR TYPES

The PIC16CXX 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

Low Power Crystal

Crystal/Resonator

High Speed Crystal/Resonator

Resistor/Capacitor

8.2.2 CRYSTAL OSCILLATOR/CERAMIC

RESONATORS

In XT, LP or HS modes a crystal or ceramic resonator

is connected to the OSC1/CLKIN and OSC2/CLKOUT

pins to establish oscillation (Figure 8-4). The

PIC16CXX 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 an external clock source to drive the OSC1/

CLKIN pin (Figure 8-5).

FIGURE 8-4:

CRYSTAL/CERAMIC

RESONATOR OPERATION

(HS, XT OR LP

OSC CONFIGURATION)

OSC1

C1

XTAL

RF

OSC2

SLEEP

PIC16CXXX

RS

C2 Note1

(2)

To internal

logic

See Table 8-1 and Table 8-1 for recommended values of

C1 and C2.

Note 1: A series resistor may be required for AT strip

cut crystals.

2: The buffer is on the OSC2 pin.

FIGURE 8-5: EXTERNAL CLOCK INPUT

OPERATION (HS, XT OR LP

OSC CONFIGURATION)

Clock from

ext. system

Open

OSC1

PIC16CXXX

OSC2

PIC16C71X

TABLE 8-1: CERAMIC RESONATORS,

PIC16C71

Ranges Tested:

Mode

Freq

OSC1

OSC2

XT

455 kHz

47 - 100 pF 47 - 100 pF

2.0 MHz

15 - 68 pF 15 - 68 pF

4.0 MHz

15 - 68 pF 15 - 68 pF

HS

8.0 MHz

15 - 68 pF 15 - 68 pF

16.0 MHz 10 - 47 pF 10 - 47 pF

These values are for design guidance only. See

notes at bottom of page.

Resonators Used:

455 kHz Panasonic EFO-A455K04B ± 0.3%

2.0 MHz Murata Erie CSA2.00MG ± 0.5%

4.0 MHz Murata Erie CSA4.00MG ± 0.5%

8.0 MHz Murata Erie CSA8.00MT ± 0.5%

16.0 MHz Murata Erie CSA16.00MX ± 0.5%

All resonators used did not have built-in capacitors.

TABLE 8-2:

CAPACITOR SELECTION

FOR CRYSTAL OSCILLATOR,

PIC16C71

Mode

Freq

OSC1

OSC2

LP

32 kHz 33 - 68 pF 33 - 68 pF

200 kHz 15 - 47 pF 15 - 47 pF

XT

100 kHz 47 - 100 pF 47 - 100 pF

500 kHz 20 - 68 pF 20 - 68 pF

1 MHz

15 - 68 pF 15 - 68 pF

2 MHz

15 - 47 pF 15 - 47 pF

4 MHz

15 - 33 pF 15 - 33 pF

HS

8 MHz

15 - 47 pF 15 - 47 pF

20 MHz 15 - 47 pF 15 - 47 pF

These values are for design guidance only. See

notes at bottom of page.

© 1997 Microchip Technology Inc.

DS30272A-page 49

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