PIC16HV785-I/SO View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16HV785-I/SO

20-Pin Flash-Based, 8-Bit CMOS Microcontroller with Two-Phase Asynchronous Feedback PWM Dual High-Speed Comparators and Dual Operational Amplifiers

Microchip Technology 

3.0 CLOCK SOURCES

3.1 Overview

The PIC16F785/HV785 has a wide variety of clock

sources and selection features to allow it to be used in

a wide range of applications while maximizing perfor-

mance and minimizing power consumption. Figure 3-1

illustrates a block diagram of the PIC16F785/HV785

clock sources.

Clock sources can be configured from external oscilla-

tors, quartz crystal resonators, ceramic resonators and

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

tem clock source can be configured from one of two

internal oscillators, with a choice of speeds selectable

via software. Additional clock features include:

• Selectable system clock source between external

or internal via software.

• Two-Speed Clock Start-up mode, which mini-

mizes 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 to the

internal oscillator.

PIC16F785/HV785

The PIC16F785/HV785 can be configured in one of

eight clock modes.

1. EC – External clock with I/O on RA4.

2. LP – 32.768 kHz Watch Crystal or Ceramic

Resonator Oscillator mode.

3. XT – Medium Gain Crystal or Ceramic

Resonator Oscillator mode.

4. HS – High Gain Crystal or Ceramic Resonator

mode.

5. RC – External Resistor-Capacitor (RC) with

FOSC/4 output on RA4

6. RCIO – External Resistor-Capacitor with I/O on

RA4.

7. INTOSC – Internal Oscillator with FOSC/4 output

on RA4 and I/O on RA5.

8. INTOSCIO – Internal Oscillator with I/O on RA4

and RA5.

Clock Source modes are configured by the

FOSC<2:0> bits in the Configuration Word (see

Section 15.0 “Special Features of the CPU”). Once

the PIC16F785/HV785 is programmed and the Clock

Source mode configured, it cannot be changed in the

software.

FIGURE 3-1:

PIC16F785/HV785 CLOCK SOURCE BLOCK DIAGRAM

OSC2

OSC1

External Oscillator

Sleep

Internal Oscillator

HFINTOSC

8 MHz

LFINTOSC

31 kHz

FOSC<2:0>

(Configuration Word)

SCS

(OSCCON<0>)

LP, XT, HS, RC, RCIO, EC

IRCF<2:0>

(OSCCON<6:4>)

8 MHz

111

4 MHz

110

2 MHz

101

1 MHz

100

500 kHz

011

250 kHz

010

125 kHz

001

31 kHz 000

System Clock

(CPU and Peripherals)

Power-up Timer (PWRT)

Watchdog Timer (WDT)

Fail-Safe Clock Monitor (FSCM)

© 2008 Microchip Technology Inc.

DS41249E-page 23

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