PIC16F570-ISLASHSP datasheet(39/129 Pages) MICROCHIP

39 / 129 page

 2013-2014 Microchip Technology Inc.

DS40001684E-page 39

PIC16F570

8.3

Oscillator Configurations

8.3.1

OSCILLATOR TYPES

The PIC16F570 device can be operated in up to six

different oscillator modes. The user can program up to

three Configuration bits (FOSC<2:0>). To select one of

these modes:

• LP:

Low-Power Crystal

• XT:

Crystal/Resonator

• HS:

High-Speed Crystal/Resonator

• INTRC: Internal 4/8 MHz Oscillator

• EXTRC: External Resistor/Capacitor

• EC:

External High-Speed Clock Input

8.3.2

CRYSTAL OSCILLATOR/CERAMIC

RESONATORS

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

is connected to the OSC1/CLKIN and OSC2/CLKOUT

pins

establish

oscillation

(Figure 8-1).

The

PIC16F570 oscillator designs require 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 HS, XT or LP modes, the

device can have an external clock source drive the

OSC1/CLKIN pin (Figure 8-2). In this mode, the output

drive levels on the OSC2 pin are very weak. If the part

is used in this fashion, then this pin should be left open

and unloaded. Also when using this mode, the external

clock should observe the frequency limits for the Clock

mode chosen (HS, XT or LP).

FIGURE 8-1:

CRYSTAL OPERATION

(OR CERAMIC

RESONATOR)

(HS, XT OR LP OSC

CONFIGURATION)

FIGURE 8-2:

EXTERNAL CLOCK INPUT

OPERATION (HS, XT, LP

OR EC OSC

CONFIGURATION)

TABLE 8-1:

CAPACITOR SELECTION FOR

CERAMIC RESONATORS

Note 1: This device has been designed to

perform to the parameters of its data

sheet. It has been tested to an electrical

specification designed to determine its

conformance with these parameters.

Due to process differences in the

manufacture of this device, this device

may

have

different

performance

characteristics than its earlier version.

These differences may cause this device

to perform differently in your application

than the earlier version of this device.

2: The user should verify that the device

oscillator

starts

and

performs

expected.

Adjusting

the

capacitor values and/or the Oscillator

mode may be required.

Osc.

Type

Resonator

Freq.

Cap. Range

4.0 MHz

30 pF

16 MHz

10-47 pF

Note 1: These values are for design guidance

only. Since each resonator has its own

characteristics, the user should consult

the

resonator

manufacturer

for

appropriate

values

external

components.

Note 1:

See Capacitor Selection tables for

recommended values of C1 and C2.

A series resistor (RS) may be required for AT

strip cut crystals.

RF approx. value = 10 M

.

C1(1)

C2(1)

XTAL

OSC2

OSC1

RF(3)

Sleep

To internal

logic

RS(2)

PIC® Device

Clock From

ext. system

PIC® Device

OSC2/CLKOUT

OSC1/CLKIN

OSC2/CLKOUT(1)

EC, HS, XT, LP

Note 1: Available in EC mode only.

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