PIC18F1220 MICROCHIP [Microchip Technology], PIC18F1220 Datasheet - Page 174

• Manufacturer Part Number: PIC18F1220
• Description: 18/20/28-Pin High-Performance, Enhanced Flash Microcontrollers with 10-bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F1220/1320
REGISTER 19-1:
DS39605C-page 172
bit 7
bit 6
bit 5-4
bit 3-0
CONFIG1H: CONFIGURATION REGISTER 1 HIGH (BYTE ADDRESS 300001h)
IESO: Internal External Switchover bit
1 = Internal External Switchover mode enabled
0 = Internal External Switchover mode disabled
FSCM: Fail-Safe Clock Monitor Enable bit
1 = Fail-Safe Clock Monitor enabled
0 = Fail-Safe Clock Monitor disabled
Unimplemented: Read as ‘0’
FOSC<3:0>: Oscillator Selection bits
11xx = External RC oscillator, CLKO function on RA6
1001 = Internal RC oscillator, CLKO function on RA6 and port function on RA7
1000 = Internal RC oscillator, port function on RA6 and port function on RA7
0111 = External RC oscillator, port function on RA6
0110 = HS oscillator, PLL enabled (clock frequency = 4 x FOSC1)
0101 = EC oscillator, port function on RA6
0100 = EC oscillator, CLKO function on RA6
0010 = HS oscillator
0001 = XT oscillator
0000 = LP oscillator
bit 7
Legend:
R = Readable bit
-n = Value when device is unprogrammed
R/P-1
IESO
FSCM
R/P-1
P = Programmable bit
U-0
—
U-0
—
FOSC3
R/P-1
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
FOSC2
R/P-1
 2004 Microchip Technology Inc.
FOSC1
R/P-1
FOSC0
R/P-1
bit 0