Datasheet
2009-2016 Microchip Technology Inc. DS60001156J-page 95
PIC32MX5XX/6XX/7XX
8.0 OSCILLATOR
CONFIGURATION
The Oscillator module has the following features:
• A total of four external and internal oscillator
options as clock sources
• On-chip PLL with user-selectable input divider,
multiplier and output divider to boost operating
frequency on select internal and external
oscillator sources
• On-chip user-selectable divisor postscaler on
select oscillator sources
• Software-controllable switching between
various clock sources
• A Fail-Safe Clock Monitor (FSCM) that detects
clock failure and permits safe application recovery
or shutdown
• Dedicated On-Chip PLL for USB peripheral
Figure 8-1shows the Oscillator module block diagram.
FIGURE 8-1: OSCILLATOR BLOCK DIAGRAM
Note: This data sheet summarizes the features
of the PIC32MX5XX/6XX/7XX family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 6. “Oscillator”
(DS60001112) in the “PIC32 Family Ref-
erence Manual”, which is available from
the Microchip web site (www.micro-
chip.com/PIC32).
Timer1, RTCC
Clock Control Logic
Fail-Safe
Clock
Monitor
FSCM INT
FSCM Event
COSC<2:0>
NOSC<2:0>
OSWEN
FSCMEN<1:0>
PLL
Secondary Oscillator (S
OSC
)
SOSCEN and FSOSCEN
SOSCO
SOSCI
XTPLL, HSPLL,
XT, HS, EC
CPU and Select Peripherals
Peripherals
FRCDIV<2:0>
WDT, PWRT
8 MHz typical
FRC
31.25 kHz typical
FRC
Oscillator
LPRC
Oscillator
S
OSC
LPRC
FRCDIV
ECPLL, FRCPLL
TUN<5:0>
div 16
Postscaler
FPLLIDIV<2:0>
PBDIV<1:0>
FRC/16
Postscaler
PLL Multiplier
COSC<2:0>
F
IN
div x div y
PLL Output Divider
PLLODIV<2:0>
PLL Input Divider
div x
32.768 kHz
PLLMULT<2:0>
PBCLK
UF
IN
4 MHz
PLL x24
USB Clock (48 MHz)
div 2
UPLLEN
UFRCEN
div x
UPLLIDIV<2:0>
UF
IN
4 MHz
F
IN
5 MHz
USB PLL
SYSCLK
Primary Oscillator
C1
(3)
C2
(3)
XTAL
R
S
(1)
Enable
OSC2
(4)
OSC1
R
F
(2)
To Internal
Logic
(P
OSC
)
R
P
(1)
Notes: 1.
A series resistor, R
S
, may be required for AT strip cut crystals or eliminate
clipping. Alternately, to increase oscillator circuit gain, add a parallel
resistor, R
P
, with a value of 1 M
2.
The internal feedback resistor, R
F
, is typically in the range of 2 to 10 M
3.
Refer to the “
PIC32 Family Reference Manual
”
Section 6. “Oscillator
Configuration”
(DS60001112) for help determining the best oscillator
components.
4.
PBCLK out is available on the OSC2 pin in certain clock modes.
(
001
= FRC,
011
= P
OSC
)
COSC<2:0>