Datasheet

dsPIC33FJ06GS001/101A/102A/202A and dsPIC33FJ09GS302
DS75018C-page 126  2011-2012 Microchip Technology Inc.
8.4 Oscillator Control Registers
REGISTER 8-1: OSCCON: OSCILLATOR CONTROL REGISTER
(1,3)
U-0 R-0 R-0 R-0 U-0 R/W-y R/W-y R/W-y
— COSC<2:0> — NOSC<2:0>
(2)
bit 15 bit 8
R/W-0 R/W-0 R-0 U-0 R/C-0 U-0 U-0 R/W-0
CLKLOCK IOLOCK LOCK
—CF — —OSWEN
bit 7 bit 0
Legend: y = Value set from Configuration bits on POR
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 (read-only)
111 = Fast RC Oscillator (FRC) with divide-by-n
110 = Fast RC Oscillator (FRC) with divide-by-16
101 = Low-Power RC Oscillator (LPRC)
100 = Reserved
011 = Primary Oscillator (XT, HS, EC) with PLL
010 = Primary Oscillator (XT, HS, EC)
001 = Fast RC Oscillator (FRC) with PLL
000 = Fast RC Oscillator (FRC)
bit 11 Unimplemented: Read as ‘0’
bit 10-8 NOSC<2:0>: New Oscillator Selection bits
(2)
111 = Fast RC Oscillator (FRC) with divide-by-n
110 = Fast RC Oscillator (FRC) with divide-by-16
101 = Low-Power RC Oscillator (LPRC)
100 = Reserved
011 = Primary Oscillator (XT, HS, EC) with PLL
010 = Primary Oscillator (XT, HS, EC)
001 = Fast RC Oscillator (FRC) with PLL
000 = Fast RC Oscillator (FRC)
bit 7 CLKLOCK: Clock Lock Enable bit
If clock switching is enabled and FSCM is disabled,
FCKSM<1:0> (FOSC<7:6>) bits = 0b01):
1 = Clock switching is disabled, system clock source is locked
0 = Clock switching is enabled, system clock source can be modified by clock switching
bit 6 IOLOCK: Peripheral Pin Select Lock bit
1 = Peripherial Pin Select is locked, write to Peripheral Pin Select registers is not allowed
0 = Peripherial Pin Select is not locked, write to Peripheral Pin Select registers is allowed
bit 5 LOCK: PLL Lock Status bit (read-only)
1 = Indicates that PLL is in lock or PLL start-up timer is satisfied
0 = Indicates that PLL is out of lock, start-up timer is in progress or PLL is disabled
Note 1: Writes to this register require an unlock sequence. Refer to Section 42. “Oscillator (Part IV)” (DS70307)
in the “dsPIC33F/PIC24H Family Reference Manual” for details.
2: Direct clock switches between any Primary Oscillator mode with PLL and FRCPLL mode are not permit-
ted. This applies to clock switches in either direction. In these instances, the application must switch to
FRC mode as a transition clock source between the two PLL modes.
3: This register is reset only on a Power-on Reset (POR).