Datasheet

 2009-2012 Microchip Technology Inc. DS70592D-page 123
PIC24HJXXXGPX06A/X08A/X10A
9.0 OSCILLATOR
CONFIGURATION
The PIC24HJXXXGPX06A/X08A/X10A oscillator
system provides:
• Various external and internal oscillator options as
clock sources
• An on-chip PLL to scale the internal operating
frequency to the required system clock frequency
• The internal FRC oscillator 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 Figure 9-1.
FIGURE 9-1: PIC24HJXXXGPX06A/X08A/X10A OSCILLATOR SYSTEM DIAGRAM
Note 1: This data sheet summarizes the features
of the PIC24HJXXXGPX06A/X08A/X10A
family of devices. However, 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 “dsPIC33F/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.
Secondary Oscillator
LPOSCEN
SOSCO
SOSCI
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
(1)
FCY
FOSC
FRCDIV
DOZE
Note 1: See Figure 9-2 for PLL details.
2: If the Oscillator is used with XT or HS modes, an extended parallel resistor with the value of 1 M must be connected.
3: The term,
FP refers to the clock source for all the peripherals, while FCY refers to the clock source for the CPU. Through-
out this document
FP and FCY are used interchangeably, except in the case of Doze mode. FP and FCY will be different
when Doze mode is used in any ratio other than 1:1, which is the default.
OSC2
OSC1
Primary Oscillator
R
(2)
POSCMD<1:0>
FP
(3)