Clock Modulator Control Register (Cmcr) - Fujitsu MB90390 Series Hardware Manual

6.3.1

Clock Modulator Control Register (CMCR)

The Clock Modulator Control Register (CMCR) has the following functions:
• Set the modulator to power down mode
• Modulator enable/disable in phase or frequency modulation mode
• Indicates the status of the modulator
■ Clock Modulator Control Register (CMCR)
Figure 6.3-2 Configuration of the Clock Modulator Control Register (CMCR)
bit 7
Address:
Re-
PMOD
0035C2
served
H
R/W R/W R/W R/W
R/W : Readable and writable
R : Read only
X : Undefined value
- : Undefined
: Initial value
The clock modulator offers two different operation modes:
• phase modulation
• frequency modulation
In general frequency modulation results in better EMI behavior.
The phase modulation mode can be enabled with just one bit (PMOD). There is no additional configuration
necessary.
The remaining bits (FMODRUN, FMOD, PDX) control or indicate the status of the frequency modulation
mode. Frequency modulation mode needs some additional configuration (CMPR register).
6 5 4 3 2 1
FMOD
Re- Re-
- FMOD PDX
served served
RUN
- R R/W R/W
0
CMCR
Initial value
0 0 0 1 X 0 0 0
B
bit 0
PDX
power down mode
0
power up mode
1
bit 1
FMOD Frequency modulation enable bit
0 Frequency modulation mode disabled
1 Frequency modulation mode enabled
bit 2
FMOD
Modulator status in frequency modulation mode
RUN
Clock frequency unmodulated or phase modulated
0
1 Clock frequency modulated
bit 4 to bit 6
Reserved
bit 4 Always write "1" to this bit
bit 5, bit 6
Always write "0" to these bit
bit 7
PMOD
0
Phase modulation disabled
1
Phase modulation enabled
CHAPTER 6 CLOCK MODULATOR
Power down bit
Reserved
Phase modulation enabled
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