Clock Modes - Fujitsu F2MC-8FX Hardware Manual

Clock Modes

There are three clock modes available: main clock mode, main PLL clock mode and subclock mode.
Table 6.1-1 shows the relationships between the clock modes and the machine clock (operating clock for
the CPU and peripheral resources).
Table 6.1-1 Clock Modes and Machine Clock Selection
Clock Mode
Main clock mode
Main PLL clock mode
Subclock mode
(Two-system clock product only)
In any of the clock modes, the selected clock can also be frequency-divided. Additionally, in modes using a
PLL clock, a multiplier for the clock frequency can also be set.
Peripheral Resources not Affected by Clock Mode
Note that the peripheral resources listed in the table below are not affected by the clock mode, division, and
PLL multiplier settings. Table 6.1-2 lists the peripheral resources not affected by the clock mode.
Table 6.1-2 Peripheral Resources Not Affected by Clock Mode
Peripheral Resource
Timebase timer
Watchdog timer
Watch prescaler
(Two-system clock product only)
Clock counter
(Two-system clock product only)
For some peripheral resources other than those listed above, it may be possible to select the timebase timer
or watch prescaler output as a count clock. Check the description of each peripheral resource for details.
The machine clock is generated from the main clock (main clock divided by 2).
The machine clock is generated from the main PLL clock (main clock multiplied by
the PLL multiplier).
The machine clock is generated from the subclock (subclock divided by 2).
1
Main clock (2 /F : main clock divided by 2)
CH
Main clock (with timebase timer output selected)
Subclock (with watch prescaler output selected) (Two-system clock product only)
1
Subclock (2 /F : subclock divided by 2)
CL
Subclock (watch prescaler output)
CHAPTER 6 CLOCK CONTROLLER
Machine Clock
Operating Clock
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