Datasheet

Table Of Contents
© 2009 Microchip Technology Inc. DS39689F-page 37
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 3-2: OSCCON: OSCILLATOR CONTROL REGISTER
R/W-0 R/W-1 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
bit 7 IDLEN: Idle Enable bit
1 = Device enters an Idle mode when a SLEEP instruction is executed
0 = Device enters Sleep mode when a SLEEP instruction is executed
bit 6-4 IRCF<2:0>: Internal Oscillator Frequency Select bits
111 = 8 MHz (INTOSC drives clock directly)
110 = 4MHz
101 = 2MHz
100 = 1MHz
(3)
011 = 500 kHz
010 = 250 kHz
001 = 125 kHz
000 = 31 kHz (from either INTOSC/256 or INTRC directly)
(2)
bit 3 OSTS: Oscillator Start-up Time-out Status bit
(1)
1 = Oscillator Start-up Timer (OST) time-out has expired; primary oscillator is running
0 = Oscillator Start-up Timer (OST) 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: Reset state depends on state of the IESO Configuration bit.
2: Source selected by the INTSRC bit (OSCTUNE<7>), see text.
3: Default output frequency of INTOSC on Reset.
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