Microchip Technology MA240029 データシート

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 2010-2011 Microchip Technology Inc.
DS39996F-page 145
PIC24FJ128GA310 FAMILY
9.0
OSCILLATOR 
CONFIGURATION
The oscillator system for PIC24FJ128GA310 family
devices has the following features:
• A total of four external and internal oscillator options 
as clock sources, providing 11 different clock modes
• On-chip 4x PLL to boost internal operating frequency 
on select internal and external oscillator sources
• Software-controllable switching between various 
clock sources
• Software-controllable postscaler for selective 
clocking of CPU for system power savings
• A Fail-Safe Clock Monitor (FSCM) that detects 
clock failure and permits safe application recovery 
or shutdown
• A separate and independently configurable system 
clock output for synchronizing external hardware
A simplified diagram of the oscillator system is shown
in 
.
FIGURE 9-1:
PIC24FJ128GA310 FAMILY CLOCK DIAGRAM 
Note:
This data sheet summarizes the features of
this group of PIC24F devices. It is not
intended to be a comprehensive reference
source. For more information, refer to the
“PIC24F Family Reference Manual”
,
“Section 6. Oscillator”
 (DS39700).
Secondary Oscillator
SOSCEN
Enable
Oscillator
SOSCO
SOSCI
Clock Source Option 
for Other Modules
OSCI
OSCO
Primary Oscillator
XT, HS, EC
P
ostscale
r
CLKDIV<10:8>
WDT, PWRT
8 MHz
FRCDIV
31 kHz (nominal)
FRC
Oscillator
LPRC
Oscillator
SOSC
LPRC
Clock Control Logic
Fail-Safe
Clock
Monitor
FRC
(nominal)
4 x PLL
8 MHz
4 MHz
CPU
Peripherals
P
ostscale
r
CLKDIV<14:12>
CLKO
Reference Clock
Generator
REFO
REFOCON<15:8>
XTPLL, HSPLL,
ECPLL, FRCPLL