Datasheet

PIC18F2331/2431/4331/4431

DS39616D-page 36  2010 Microchip Technology Inc.

R/W-0 R/W-0 R/W-0 R/W-0 R

(1)

R-0 R/W-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.