Microchip Technology MA330016 数据表

© 2007-2011 Microchip Technology Inc.

DS70290J-page 97

The dsPIC33FJ32GP202/204 and dsPIC33FJ16GP304
oscillator system provides:
• External and internal oscillator options as clock 

sources.

• An on-chip PLL to scale the internal operating 

frequency to the required system clock frequency.

• An internal FRC oscillator that can also be used 

with the PLL, thereby allowing full-speed 
operation without any external clock generation 
hardware.

• Clock switching between various clock sources.
• Programmable clock postscaler for system power 

savings.

• A Fail-Safe Clock Monitor (FSCM) that detects 

clock failure and takes fail-safe measures.

• An Oscillator Control register (OSCCON).
• Nonvolatile Configuration bits for main oscillator 

selection.

A simplified diagram of the oscillator system is shown
in 

.

Note 1: This data sheet summarizes the features

of the dsPIC33FJ32GP202/204 and
dsPIC33FJ16GP304 family of devices. It
is not intended to be a comprehensive
reference source. To complement the
information in this data sheet, refer to
Section 7. “Oscillator” (DS70186) of
the 

Reference Manual”, which is available
from the Microchip web site
(

www.microchip.com

).

2: Some registers and associated bits

described in this section may not be
available on all devices. Refer to

 in

this data sheet for device-specific register
and bit information.

 for PLL details.

2: If the Oscillator is used with XT or HS modes, an external parallel resistor with the value of 1 M

Ω must be connected.

3: The term 

F

P

 refers to the clock source for all of the peripherals, while 

F

CY

 refers to the clock source for the CPU.

Throughout this document, 

F

CY

 and 

F

P

 are used interchangeably, except in the case of DOZE mode. 

F

P

 and 

F

CY

 will

be different when DOZE mode is used with any ratio other than 1:1 which is the default.

Secondary Oscillator (S

OSC

)

LPOSCEN

SOSCO

Timer 1

XTPLL, HSPLL,

XT, HS, EC

FRCDIV<2:0> 

WDT, PWRT, 

FSCM

FRCDIVN

SOSC

FRCDIV16

ECPLL, FRCPLL

NOSC<2:0> FNOSC<2:0>

Reset

FRC

Oscillator

LPRC

Oscillator

DOZE<2:0>

S3

S1

S2

S1/S3

S7

S6

FRC 

LPRC

S0

S5

S4

÷ 16

Clock Switch

S7

Clock Fail

÷ 2

TUN<5:0>

PLL

F

CY(3)

F

OSC

FRC

D

IV

DOZE

OSC2

OSC1

Primary Oscillator (P

OSC

)

R

POSCMD<1:0>

F

P(3)

SOSCI