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S3C2440A RISC MICROPROCESSOR CLOCK & POWER MANAGEMENT
7-5
Divider
P
Loop Filter
Fin
M[7:0]
S[1:0]
PFD
Divider
M
P[5:0]
F
vco
PUMP
VCO
Divider
S
F
ref
MPLL,UPLL
R
C
Internal
C
LF
External
MPLLCAP,
UPLLCAP
Figure 7-2. PLL (Phase-Locked Loop) Block Diagram
EXTCLK
XTIpll
XTOpll
EXTCLK
XTIpll
XTOpll
External
OSC
a) X-TAL Oscillation (OM[3:2]=00) b) External Clock Source (OM[3:2]=11)
V
DD
V
DD
C
EXT
C
EXT
Figure 7-3. Main Oscillator Circuit Examples