Specifications
11
AT83SND2CMP3
7524D–MP3–07/07
Figure 7). Value o f the filter com ponents are detailed in the Section “ DC
Characteristics”.
The VCO block is the Voltage Controlled Oscillator controlled by the voltage V
ref
pro-
duced by the charge pump. It generates a square wave signal: the PLL clock.
Figure 6. PLL Block Diagram and Symbol
Figure 7. PLL Filter Connection
PLL Programming The PLL is programmed using the flow shown in Figure 8. The PLL clock frequency will
depend on MP3 decoder clock and audio interface clock frequencies.
Figure 8. PLL Programming Flow
PLLEN
PLLCON.1
N6:0
N divider
R divider
VCO
PLLclk
OSCclk R 1+( )
×
N 1+
-----------------------------------------------=
OSC
CLOCK
PFLD
PLOCK
PLLCON.0
PFILT
CHP
Vref
Up
Down
R9:0
PLL
CLOCK
PLL Clock Symbol
PLL
Clock
VSS
FILT
R
C1
C2
VSS
PLL
Programming
Configure Dividers
N6:0 = xxxxxxb
R9:0 = xxxxxxxxxxb
Enable PLL
PLLRES = 0
PLLEN = 1
PLL Locked?
PLOCK = 1?