Datasheet

 2011-2012 Microchip Technology Inc. DS70652E-page 125
dsPIC33FJ16(GP/MC)101/102 AND dsPIC33FJ32(GP/MC)101/102/104
8.0 OSCILLATOR
CONFIGURATION
The oscillator system for dsPIC33FJ16(GP/MC)101/
102 and dsPIC33FJ32(GP/MC)101/102/104 devices
provides:
• External and internal oscillator options as clock
sources
• An on-chip, 4x Phase Lock Loop (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
• A Clock Control register (OSCCON)
• Nonvolatile Configuration bits for main oscillator
selection
A simplified diagram of the oscillator system is shown
in Figure 8-1.
FIGURE 8-1: OSCILLATOR SYSTEM DIAGRAM
Note 1: This data sheet summarizes the features
of the dsPIC33FJ16(GP/MC)101/102
and dsPIC33FJ32(GP/MC)101/102/104
family devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 52. “Oscillator
(Part VI)” (DS70644) in the “dsPIC33F/
PIC24H Family 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
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
Note 1: If the oscillator is used with MS or HS modes, an extended parallel resistor with the value of 1 M must be connected.
2: The term, F
P, refers to the clock source for all peripherals, while FCY refers to the clock source for the CPU. Throughout this docu-
ment, F
CY and FP are used interchangeably, except in the case of Doze mode. FP and FCY will be different when Doze mode is
used with a Doze ratio of 1:2 or lower.
Secondary Oscillator (SOSC)
LPOSCEN
SOSCO
SOSCI
Timer 1
MSPLL, ECPLL,
MS, HS, EC
FRCDIV<2:0>
WDT, PWRT,
FSCM
FRCDIVN
SOSC
FRCDIV16
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>
4x PLL
F
CY
(2)
FRCDIV
DOZE
OSC2
OSC1
Primary Oscillator (POSC)
R
(1)
POSCMD<1:0>
FP
(2)
FOSC
(To Peripherals)