
PIC18(L)F2X/4XK22
DS41412E-page 28
2010-2012 Microchip Technology Inc.
FIGURE 2-1:
SIMPLIFIED OSCILLATOR SYSTEM BLOCK DIAGRAM
5: The Primary Oscillator MUX uses the INTOSC branch when FOSC<3:0> = 100x.
SOSCO
SOSCI
Secondary
Oscillator
(SOSC)
Secondary Oscillator(1)
OSC2
OSC1
Primary
Oscillator(2)
(OSC)
Primary Oscillator
0
1
FOSC<3:0>(5)
PLL_Select
(3) (4)
0
1
4xPLL
INTOSC
Primary Clock Module
Low-Power Mode
Event Switch
(SCS<1:0>)
01
00
1x
Secondary
Oscillator
2
Primary
Clock
INTOSC
Clo
ck
Switch
M
U
X
INTOSC
IRCF<2:0>
MFIOSEL
INTSRC
HF-16 MHZ
HF-8 MHZ
HF-4 MHZ
HF-2 MHZ
HF-1 MHZ
HF-31.25 kHZ
HF-250 kHZ
HF-500 kHZ
HFINTOSC
MFINTOSC
LFINTOSC
(16 MHz)
(500 kHz)
(31.25 kHz)
INTOSC
Divide
Circuit
In
te
rn
a
lOscilla
to
r
M
U
X
(3)
MF-31.25 kHZ
MF-250 kHZ
MF-500 kHZ
LF-31.25 kHz
3
Internal Oscillator
SOSCOUT
PRICLKEN
PRISD
EN