PIC12F1822-ISLASHMF datasheet(55/398 Pages) MICROCHIP

55 / 398 page

 2010 Microchip Technology Inc.

Preliminary

DS41413A-page 55

PIC12F/LF1822/16F/LF1823

5.0

OSCILLATOR MODULE (WITH

FAIL-SAFE CLOCK MONITOR)

5.1

Overview

The oscillator module has a wide variety of clock

sources and selection features that allow it to be used

in a wide range of applications while maximizing perfor-

mance and minimizing power consumption. Figure 5-1

illustrates a block diagram of the oscillator module.

Clock sources can be supplied from external oscillators,

quartz crystal resonators, ceramic resonators and

Resistor-Capacitor (RC) circuits. In addition, the system

clock source can be supplied from one of two internal

oscillators and PLL circuits, with a choice of speeds

selectable via software. Additional clock features

include:

• Selectable system clock source between external

or internal sources via software.

• Two-Speed Start-up mode, which minimizes

latency between external oscillator start-up and

code execution.

• Fail-Safe Clock Monitor (FSCM) designed to

detect a failure of the external clock source (LP,

XT, HS, EC or RC modes) and switch

automatically to the internal oscillator.

• Oscillator Start-up Timer (OST) ensures stability

of crystal oscillator sources

The oscillator module can be configured in one of six

clock modes.

EC – External clock (ECL, ECM, ECH. See

Section 5.2.1.1 “EC Mode”).

LP – 32 kHz Low-Power Crystal mode.

XT – Medium Gain Crystal or Ceramic Resonator

Oscillator mode.

HS – High Gain Crystal or Ceramic Resonator

mode.

RC – External Resistor-Capacitor (RC).

INTOSC – Internal oscillator.

Clock Source modes are selected by the FOSC<2:0>

bits in the Configuration Word 1. The FOSC bits

determine the type of oscillator that will be used when

the device is first powered.

The EC clock mode relies on an external logic level

signal as the device clock source. The LP, XT, and HS

clock modes require an external crystal or resonator to

be connected to the device. Each mode is optimized for

a different frequency range. The RC clock mode

requires an external resistor and capacitor to set the

oscillator frequency.

The INTOSC internal oscillator block produces low,

medium, and high frequency clock sources, designated

LFINTOSC, MFINTOSC, and HFINTOSC. (see

Internal Oscillator Block, Figure 5-1). A wide selection

of device clock frequencies may be derived from these

three clock sources.

FIGURE 5-1:

SIMPLIFIED PIC® MCU CLOCK SOURCE BLOCK DIAGRAM

4 x PLL

FOSC<2:0>

Oscillator

T1OSCEN

Enable

Oscillator

T1OSO

T1OSI

Clock Source Option

for other modules

OSC1

OSC2

Sleep

LP, XT, HS, RC, EC

T1OSC

CPU and

16 MHz

8 MHz

4 MHz

2 MHz

1 MHz

250 kHz

500 kHz

IRCF<3:0>

31 kHz

500 kHz

Source

Internal

Oscillator

Block

WDT, PWRT, Fail-Safe Clock Monitor

16 MHz

Internal Oscillator

(HFINTOSC)

Clock

Control

SCS<1:0>

HFPLL

31 kHz (LFINTOSC)

Two-Speed Start-up and other modules

Oscillator

31 kHz

Source

500 kHz

(MFINTOSC)

125 kHz

31.25 kHz

62.5 kHz

FOSC<2:0> = 100

Peripherals

Sleep

External

Timer1

PIC12F1822-I/MF Datasheet(PDF) 55 Page - Microchip Technology

PIC12F1822-I/MF Datasheet(HTML) 55 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Descarga

Enlace URL