PIC16C716T-04I/SO View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16C716T-04I/SO

8-Bit CMOS Microcontrollers with A/D Converter and Capture/Compare/PWM

Microchip Technology 

9.2 Oscillator Configurations

9.2.1 OSCILLATOR TYPES

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

Low Power Crystal

Crystal/Resonator

High Speed Crystal/Resonator

Resistor/Capacitor

9.2.2 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 9-2). The

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 an external clock source to drive the

OSC1/CLKIN pin (Figure 9-3).

FIGURE 9-2:

C1(1)

CRYSTAL/CERAMIC

RESONATOR OPERATION

(HS, XT OR LP

OSC CONFIGURATION)

OSC1

XTAL

OSC2

RS(2)

C2(1)

RF(3)

To

internal

logic

SLEEP

PIC16C7XX

Note 1: See Table 9-1 and Table 9-2 for recom-

mended values of C1 and C2.

2: A series resistor (RS) may be required for

AT strip cut crystals.

3: RF varies with the crystal chosen.

FIGURE 9-3:

EXTERNAL CLOCK INPUT

OPERATION (HS, XT OR LP

OSC CONFIGURATION)

Clock from

ext. system

Open

OSC1

PIC16C7XX

OSC2

PIC16C712/716

TABLE 9-1 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.

TABLE 9-2

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: Recommended values of C1 and C2 are

identical to the ranges tested (Table 9-1).

2: Higher capacitance increases the stability

of the oscillator, but also increases the start-

up time.

3: Since each resonator/crystal has its own

characteristics, the user should consult the

resonator/crystal manufacturer for appropri-

ate values of external components.

4: Rs may be required in HS mode, as well as

XT mode to avoid overdriving crystals with

low drive level specification.

© 1999 Microchip Technology Inc.

Preliminary

DS41106A-page 53

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