FR, MB91460, FR Clocks
Document No. 002-05317 Rev. *C
17
6
Clock Modulator Configuration
The Clock Modulator has the start up time of 6
μs after it is powered on (using the
PDX
bit of Clock Modulation
Control Register (
CMCR
) register). The following are the prerequisites to enable the clock modulator (using the
MODEN
bit of
CMCR
register):
▪
The PLL lock time is elapsed and it is stabilized (i.e.
PCM
bit of
CKMR
register is set)
▪
Clock Modulator is powered up and the start up time is elapsed.
▪
The Clock Modulator Parameter Register (
CMPR)
register is configured with the appropriate value.
The
MODRUN
bit of the
CMCR
register reflects the status of modulated clock. If it is 1 then the CLKMOD can be used as
a clock resource for CLKS1.
The
CMPR
register contains modulation parameter which determines the degree of modulation and the maximal and
minimal occurring frequencies in the modulated clock. Please refer the hardware manual for the correspondence
between PLL frequency and possible modulation parameters.
In order to power down the clock modulator its needs to be disabled (using the
MODEN
bit of
CMCR
register). After
that, once the
MODRUN
bit gets cleared to zero, the clock modulator can be powered down.