Datasheet

dsPIC33FJXXXGPX06/X08/X10
DS70286C-page 140 © 2009 Microchip Technology Inc.
REGISTER 9-1: OSCCON: OSCILLATOR CONTROL REGISTER
(1)
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 U-0 R-0 U-0 R/C-0 U-0 R/W-0 R/W-0
CLKLOCK —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)
000 = Fast RC oscillator (FRC)
001 = Fast RC oscillator (FRC) with PLL
010 = Primary oscillator (XT, HS, EC)
011 = Primary oscillator (XT, HS, EC) with PLL
100 = Secondary oscillator (SOSC)
101 = Low-Power RC oscillator (LPRC)
110 = Fast RC oscillator (FRC) with Divide-by-16
111 = Fast RC oscillator (FRC) with Divide-by-n
bit 11 Unimplemented: Read as ‘0’
bit 10-8 NOSC<2:0>: New Oscillator Selection bits
(2)
000 = Fast RC oscillator (FRC)
001 = Fast RC oscillator (FRC) with PLL
010 = Primary oscillator (XT, HS, EC)
011 = Primary oscillator (XT, HS, EC) with PLL
100 = Secondary oscillator (SOSC)
101 = Low-Power RC oscillator (LPRC)
110 = Fast RC oscillator (FRC) with Divide-by-16
111 = Fast RC oscillator (FRC) with Divide-by-n
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 Unimplemented: Read as ‘0’
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’
bit 3 CF: Clock Fail Detect bit (read/clear by application)
1 = FSCM has detected clock failure
0 = FSCM has not detected clock failure
bit 2 Unimplemented: Read as ‘0’
Note 1: Writes to this register require an unlock sequence. Refer to Section 7. “Oscillator” (DS70186) in the
“dsPIC33F Family Reference Manual” (available from the Microchip website) 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.