Microchip Technology MA160014 Data Sheet
2010-2012 Microchip Technology Inc.
DS41412F-page 357
PIC18(L)F2X/4XK22
24.2
Register Definitions: Configuration Word
REGISTER 24-1:
CONFIG1H: CONFIGURATION REGISTER 1 HIGH
R/P-0
R/P-0
R/P-1
R/P-0
R/P-0
R/P-1
R/P-0
R/P-1
IESO
FCMEN
PRICLKEN
PLLCFG
FOSC<3:0>
bit 7
bit 0
Legend:
R = Readable bit
P = Programmable bit
U = Unimplemented bit, read as ‘0’
-n = Value when device is unprogrammed
x = Bit is unknown
bit 7
IESO
(1)
: Internal/External Oscillator Switchover bit
1
= Oscillator Switchover mode enabled
0
= Oscillator Switchover mode disabled
bit 6
FCMEN
(1)
: Fail-Safe Clock Monitor Enable bit
1
= Fail-Safe Clock Monitor enabled
0
= Fail-Safe Clock Monitor disabled
bit 5
PRICLKEN: Primary Clock Enable bit
1
= Primary Clock is always enabled
0
= Primary Clock can be disabled by software
bit 4
PLLCFG: 4 x PLL Enable bit
1
= 4 x PLL always enabled, Oscillator multiplied by 4
0
= 4 x PLL is under software control, PLLEN (OSCTUNE<6>)
bit 3-0
FOSC<3:0>: Oscillator Selection bits
1111
= External RC oscillator, CLKOUT function on RA6
1110
= External RC oscillator, CLKOUT function on RA6
1101
= EC oscillator (low power, <500 kHz)
1100
= EC oscillator, CLKOUT function on OSC2 (low power, <500 kHz)
1011
= EC oscillator (medium power, 500 kHz-16 MHz)
1010
= EC oscillator, CLKOUT function on OSC2 (medium power, 500 kHz-16 MHz)
1001
= Internal oscillator block, CLKOUT function on OSC2
1000
= Internal oscillator block
0111
= External RC oscillator
0110
= External RC oscillator, CLKOUT function on OSC2
0101
= EC oscillator (high power, >16 MHz)
0100
= EC oscillator, CLKOUT function on OSC2 (high power, >16 MHz)
0011
= HS oscillator (medium power, 4 MHz-16 MHz)
0010
= HS oscillator (high power, >16 MHz)
0001
= XT oscillator
0000
= LP oscillator
Note 1:
When FOSC<3:0> is configured for HS, XT, or LP oscillator and FCMEN bit is set, then the IESO bit
should also be set to prevent a false failed clock indication and to enable automatic clock switch over from
the internal oscillator block to the external oscillator when the OST times out.
should also be set to prevent a false failed clock indication and to enable automatic clock switch over from
the internal oscillator block to the external oscillator when the OST times out.