PIC18F2221 MICROCHIP [Microchip Technology], PIC18F2221 Datasheet - Page 256

• Manufacturer Part Number: PIC18F2221
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F4321 FAMILY
REGISTER 23-1:
DS39689E-page 254
bit 7
bit 6
bit 5-4
bit 3-0
CONFIG1H: CONFIGURATION REGISTER 1 HIGH (BYTE ADDRESS 300001h)
Legend:
R = Readable bit
-n = Value when device is unprogrammed
bit 7
IESO: Internal/External Oscillator Switchover bit
1 = Oscillator Switchover mode enabled
0 = Oscillator Switchover mode disabled
FCMEN: Fail-Safe Clock Monitor Enable bit
1 = Fail-Safe Clock Monitor enabled
0 = Fail-Safe Clock Monitor disabled
Unimplemented: Read as ‘0’
FOSC3:FOSC0: Oscillator Selection bits
11xx = External RC oscillator, CLKO function on RA6
101x = External RC oscillator, CLKO function on RA6
1001 = Internal oscillator block, CLKO function on RA6, port function on RA7
1000 = Internal oscillator block, port function on RA6 and 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
0011 = External RC oscillator, CLKO function on RA6
0010 = HS oscillator
0001 = XT oscillator
0000 = LP oscillator
R/P-0
IESO
FCMEN
R/P-0
P = Programmable bit
U-0
Preliminary
—
U-0
—
FOSC3
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
R/P-0
FOSC2
R/P-1
© 2007 Microchip Technology Inc.
FOSC1
R/P-1
FOSC0
R/P-1
bit 0