PIC32MX5XX_11 Datasheet, PDF (125/256 Pages) Microchip Technology – High-Performance, USB, CAN and Ethernet 32-bit Flash Microcontrollers

PIC32MX5XX/6XX/7XX
8.0 OSCILLATOR
CONFIGURATION
Note 1: 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”
(DS61112) in the “PIC32 Family
Reference Manual”, 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 PIC32MX5XX/6XX/7XX oscillator system has the
following modules and 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:
PIC32MX5XX/6XX/7XX FAMILY OSCILLATOR BLOCK DIAGRAM
USB PLL
C1⁽³⁾
Primary Oscillator
OSC1 ^(POSC)
XTAL
RF⁽²⁾
To Internal
Logic
Enable
RS⁽¹⁾
C2⁽³⁾ _OSC2(4)
div 2
ADC
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
PLL Input Divider
FPLLIDIV<2:0>
PLL Output Divider
PLLODIV<2:0>
PBDIV<1:0>
FRC
Oscillator
8 MHz typical
COSC<2:0>
PLL Multiplier
PLLMULT<2:0>
FRC
CPU and Select Peripherals
TUN<5:0>
div 16
FRC/16
SYSCLK
Postscaler
FRCDIV
LPRC
Oscillator
FRCDIV<2:0>
31.25 kHz typical
Secondary Oscillator (SOSC)
SOSCO
32.768 kHz
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 Section 6. “Oscillator ” (DS61112) in the “PIC32 Family
Reference Manual” for help in determining the best oscillator components.
The PBCLK out is available on the OSC2 pin in certain clock modes.
LPRC
SOSC
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
© 2009-2011 Microchip Technology Inc.
DS61156G-page 125