PIC32MX320F032H_11 Datasheet, PDF (93/214 Pages) Microchip Technology – High-Performance, General Purpose and USB, 32-bit Flash Microcontrollers

PIC32MX3XX/4XX
8.0 OSCILLATOR
CONFIGURATION
Note 1: This data sheet summarizes the features
of the PIC32MX3XX/4XX family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to the “PIC32 Family
Reference Manual” Section 6.
“Oscillator Configuration” (DS61112),
which is available from the Microchip web
site (www.microchip.com/PIC32).
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.
The PIC32MX oscillator system has the following
modules and features:
• A total of four external and internal oscillator
options as clock sources
• On-chip PLL (phase-locked loop) 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 shut down
• Dedicated on-chip PLL for USB peripheral
FIGURE 8-1:
PIC32MX3XX/4XX FAMILY CLOCK DIAGRAM
USB PLL
Primary Oscillator (POSC)
C1⁽³⁾
OSC1
XTAL
RF⁽²⁾
To Internal
Logic
Enable
UFIN
div x
PLL x24
UFIN = 4 MHz
UPLLIDIV<2:0>
div 2
USB Clock (48 MHz)
UFRCEN
UPLLEN
XT, HS, EC
4 MHz ≤ FIN ≤ 5 MHz
XTPLL, HSPLL,
FIN
ECPLL, FRCPLL
div x
PLL
div y
Postscaler ^Peripherals
div x
PBCLK
RS⁽¹⁾
C2⁽³⁾ _OSC2(4)
FRC
Oscillator
8 MHz typical
PLL Input Divider
FPLLIDIV<2:0>
PLL Output Divider
PLLODIV<2:0>
COSC<2:0>
PLL Multiplier
PLLMULT<2:0>
FRC
PBDIV<1:0>
TUN<5:0>
div 16
Postscaler
LPRC
Oscillator
FRCDIV<2:0>
31.25 kHz typical
FRC/16
FRCDIV
LPRC
CPU and Select Peripherals
SYSCLK
Secondary Oscillator (SOSC)
SOSCO
32.768 kHz
SOSC
SOSCEN and FSOSCEN
SOSCI
Notes: 1.
2.
3.
4.
A series resistor, RS, may be required for AT strip-cut crystals.
The internal feedback resistor, RF, is typically in the range of 2 to 10 MΩ.
Refer to the “PIC32 Family Reference Manual” Section 6. “Oscillator
Configuration” (DS61112) for help determining the best oscillator
components.
PBCLK out is available on the OSC2 pin in certain clock modes.
Clock Control Logic
Fail-Safe
Clock
Monitor
FSCM INT
FSCM Event
NOSC<2:0>
COSC<2:0>
FSCMEN<1:0>
OSWEN
WDT, PWRT
Timer1, RTCC
© 2011 Microchip Technology Inc.
DS61143H-page 93