PIC24FJ128GB MICROCHIP [Microchip Technology], PIC24FJ128GB Datasheet - Page 113

• Manufacturer Part Number: PIC24FJ128GB
• Description: 64/80/100-Pin, 16-Bit Flash Microcontrollers with USB On-The-Go (OTG)
• Manufacturer: MICROCHIP [Microchip Technology]

7.3
The operation of the oscillator is controlled by three
Special Function Registers:
• OSCCON
• CLKDIV
• OSCTUN
REGISTER 7-1:
© 2008 Microchip Technology Inc.
bit 15
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 15
bit 14-12
bit 11
bit 10-8
Note 1:
CLKLOCK
R/SO-0
U-0
—
2:
3:
Control Registers
Reset values for these bits are determined by the FNOSC Configuration bits.
The state of the IOLOCK bit can only be changed once an unlocking sequence has been executed. In
addition, if the IOL1WAY Configuration bit is ‘1’, once the IOLOCK bit is set, it cannot be cleared.
Also resets to ‘0’ during any valid clock switch or whenever a non-PLL clock mode is selected.
Unimplemented: Read as ‘0’
COSC2:COSC0: Current Oscillator Selection bits
111 = Fast RC Oscillator with Postscaler (FRCDIV)
110 = Reserved
101 = Low-Power RC Oscillator (LPRC)
100 = Secondary Oscillator (SOSC)
011 = Primary Oscillator with PLL module (XTPLL, HSPLL, ECPLL)
010 = Primary Oscillator (XT, HS, EC)
001 = Fast RC Oscillator with Postscaler and PLL module (FRCPLL)
000 = Fast RC Oscillator (FRC)
Unimplemented: Read as ‘0’
NOSC2:NOSC0: New Oscillator Selection bits
111 = Fast RC Oscillator with Postscaler (FRCDIV)
110 = Reserved
101 = Low-Power RC Oscillator (LPRC)
100 = Secondary Oscillator (SOSC)
011 = Primary Oscillator with PLL module (XTPLL, HSPLL, ECPLL)
010 = Primary Oscillator (XT, HS, EC)
001 = Fast RC Oscillator with Postscaler and PLL module (FRCPLL)
000 = Fast RC Oscillator (FRC)
IOLOCK
COSC2
R/W-0
R-0
OSCCON: OSCILLATOR CONTROL REGISTER
(2)
CO = Clear Only bit
W = Writable bit
‘1’ = Bit is set
COSC1
LOCK
R-0
R-0
(3)
PIC24FJ256GB110 FAMILY
COSC0
R-0
U-0
—
Preliminary
SO = Set Only bit
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
(1)
R/CO-0
The OSCCON register (Register 7-1) is the main con-
trol register for the oscillator. It controls clock source
switching and allows the monitoring of clock sources.
The CLKDIV register (Register 7-2) controls the
features associated with Doze mode, as well as the
postscaler for the FRC oscillator. The OSCTUN
register (Register 7-3) allows the user to fine tune the
FRC oscillator over a range of approximately ±12%.
U-0
CF
—
POSCEN
R/W-x
NOSC2
R/W-0
(1)
x = Bit is unknown
SOSCEN
R/W-x
NOSC1
R/W-0
(1)
DS39897B-page 111
R/W-x
OSWEN
NOSC0
R/W-0
(1)
bit 8
bit 0