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Chapter 17 Clock Modulator
2.Clock Modulator Registers
● Clock Modulation Parameter Register (CMPR)
The Modulation Parameter Register (CMPR) determines the modulation degree in frequency modulation
mode.
Figure 2-3 Modulation parameter register
• The modulation parameter determines the degree of modulation and the maximal and minimal occurring
frequencies in the modulated clock. Please refer to the application note for a description of an approach to
select the optimal setting.
• Each set of possible modulation parameters refers to a particular PLL frequency. The PLL frequency and the
selected parameter must match. Please refer to the following table of possible settings.
• The modulation parameter affects only the frequency modulation mode.
Note:
The modulation parameter must be changed only when the modulator is disabled and the RUN flag is 0
(FMOD=0, FMODRUN=0).
● Modulation parameter register contents
modulator enabled in frequency modulation mode,
modulator is calibrating, modulation not active
11 0
modulator is running in frequency modulation mode
modulation is active
11 1
others not allowed
Table 2-3 Function of each bit of the modulation parameter register (CMPR)
Bit name Function
bit 15, 14 Undefined
Table 2-2 States of the modulator
FMOD PDX
FMODRUN
(read only)
Initial value
1 1 1 1 1 1 0 1
B
R/W R/W R/W R/W R/W R/W R/W R/W
Address:
0004B9
H
CMPRL (lower)
Initial value
X X 0 0 0 0 0 1 0
B
CMPRH (upper)
0004B8
H
15 14 13 12 11 10 9 8
10325476
R/W R/W R/W R/W R/W R/W
R/W
: Readable and writable
Undefined value
X
:
: Undefined