
PIC18F2331/2431/4331/4431
DS39616D-page 36
2010 Microchip Technology Inc.
REGISTER 3-2:
OSCCON: OSCILLATOR CONTROL REGISTER
R/W-0
R(1)
R-0
R/W-0
IDLEN
IRCF2
IRCF1
IRCF0
OSTS
IOFS
SCS1
SCS0
bit 7
bit 0
Legend:
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 7
IDLEN:
Idle Enable bit
1
= Idle mode enabled; CPU core is not clocked in power-managed modes
0
= Run mode enabled; CPU core is clocked in power-managed modes
bit 6-4
IRCF<2:0>:
Internal Oscillator Frequency Select bits
111
= 8 MHz (8 MHz source drives clock directly)
110
= 4 MHz (default)
101
= 2 MHz
100
= 1 MHz
011
= 500 kHz
010
= 250 kHz
001
= 125 kHz
000
= 31 kHz (INTRC source drives clock directly)(2)
bit 3
OSTS:
Oscillator Start-up Timer Time-out Status bit(1)
1
= Oscillator Start-up Timer time-out has expired; primary oscillator is running
0
= Oscillator Start-up Timer time-out is running; primary oscillator is not ready
bit 2
IOFS:
INTOSC Frequency Stable bit
1
= INTOSC frequency is stable
0
= INTOSC frequency is not stable
bit 1-0
SCS<1:0>:
System Clock Select bits
1x
= Internal oscillator block
01
= Secondary (Timer1) oscillator
00
= Primary oscillator
Note 1:
Depends on the state of the IESO bit in Configuration Register 1H.
2:
Default output frequency of INTOSC on Reset.