Datasheet

© 2009-2012 Microchip Technology Inc. Preliminary DS70616F-page 181
dsPIC33EPXXX(GP/MC/MU)806/810/814 and PIC24EPXXX(GP/GU)810/814
9.3 Oscillator Registers
REGISTER 9-1: 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 R/W-0 R/W-0
CLKLOCK IOLOCK LOCK
—CF — LPOSCEN 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 = Secondary Oscillator (S
OSC)
011 = Primary Oscillator (XT, HS, EC) with PLL
010 = Primary Oscillator (XT, HS, EC)
001 = Fast RC Oscillator (FRC) with Divide-by-N and 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 = Secondary Oscillator (S
OSC)
011 = Primary Oscillator (XT, HS, EC) with PLL
010 = Primary Oscillator (XT, HS, EC)
001 = Fast RC Oscillator (FRC) with Divide-by-N and PLL
000 = Fast RC Oscillator (FRC)
bit 7 CLKLOCK: Clock Lock Enable bit
1 = If (FCKSM0 = 1), then clock and PLL configurations are locked
If (FCKSM0 = 0), then clock and PLL configurations may be modified
0 = Clock and PLL selections are not locked, configurations may be modified
bit 6 IOLOCK: I/O Lock Enable bit
1 = I/O Lock is active
0 = I/O Lock is not active
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
bit 4 Unimplemented: Read as ‘0’
Note 1: Writes to this register require an unlock sequence. Refer to Section 7. “Oscillator” (DS70580) in the
“dsPIC33E/PIC24E Family Reference Manual” (available from the Microchip web site) for details.
2: Direct clock switches between any primary oscillator mode with PLL and FRCPLL mode are not permitted.
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 resets only on a Power-on Reset (POR).