Microchip Technology Microstick for the 5V PIC24F K-series DM240013-2 DM240013-2 Data Sheet
Product codes
DM240013-2
2013 Microchip Technology Inc.
DS30003030B-page 123
PIC24FV16KM204 FAMILY
9.3
Control Registers
The operation of the oscillator is controlled by three
Special Function Registers (SFRs):
• OSCCON
• CLKDIV
• OSCTUN
The OSCCON register (
Special Function Registers (SFRs):
• OSCCON
• CLKDIV
• OSCTUN
The OSCCON register (
) is the main
control register for the oscillator. It controls clock
source switching and allows the monitoring of clock
sources.
source switching and allows the monitoring of clock
sources.
The Clock Divider register (
) controls the
features associated with Doze mode, as well as the
postscaler for the FRC Oscillator.
The FRC Oscillator Tune register (
postscaler for the FRC Oscillator.
The FRC Oscillator Tune register (
) allows
the user to fine-tune the FRC Oscillator over a range of
approximately ±5.25%. Each bit increment or decre-
ment changes the factory calibrated frequency of the
FRC Oscillator by a fixed amount.
approximately ±5.25%. Each bit increment or decre-
ment changes the factory calibrated frequency of the
FRC Oscillator by a fixed amount.
REGISTER 9-1:
OSCCON: OSCILLATOR CONTROL REGISTER
U-0
R-0, HSC
R-0, HSC
R-0, HSC
U-0
R/W-x
R/W-x
(
)
R/W-x
(
)
—
COSC2
COSC1
COSC0
—
NOSC2
NOSC1
NOSC0
bit 15
bit 8
R/SO-0, HSC
U-0
R-0, HSC
(
U-0
R/CO-0, HS
R/W-0
(
)
R/W-0
R/W-0
CLKLOCK
—
LOCK
—
CF
SOSCDRV
SOSCEN
OSWEN
bit 7
bit 0
Legend:
HSC = Hardware Settable/Clearable bit
HS = Hardware Settable bit
CO = Clearable Only bit
SO = Settable Only bit
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
bit 15
Unimplemented:
Read as ‘0’
bit 14-12
COSC<2:0>:
Current Oscillator Selection bits
111
= 8 MHz Fast RC Oscillator with Postscaler (FRCDIV)
110
= 500 kHz Low-Power Fast RC Oscillator (FRC) with Postscaler (LPFRCDIV)
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
= 8 MHz FRC Oscillator with Postscaler and PLL module (FRCPLL)
000
= 8 MHz FRC Oscillator (FRC)
bit 11
Unimplemented:
Read as ‘0’
bit 10-8
NOSC<2:0>:
New Oscillator Selection bits
(
111
= 8 MHz Fast RC Oscillator with Postscaler (FRCDIV)
110
= 500 kHz Low-Power Fast RC Oscillator (FRC) with Postscaler (LPFRCDIV)
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
= 8 MHz FRC Oscillator with Postscaler and PLL module (FRCPLL)
000
= 8 MHz FRC Oscillator (FRC)
Note 1:
Reset values for these bits are determined by the FNOSCx Configuration bits.
2:
This bit also resets to ‘0’ during any valid clock switch or whenever a non-PLL Clock mode is selected.
3:
When SOSC is selected to run from a digital clock input, rather than an external crystal (SOSCSRC = 0),
this bit has no effect.
this bit has no effect.