NEC 78K0 Series User Manual page 155

<2> Setting the high-speed system clock as the main system clock (MCM register)
When XSEL and MCM0 are set to 1, the high-speed system clock is supplied as the main system clock
and peripheral hardware clock.
XSEL MCM0
1
Caution If the high-speed system clock is selected as the main system clock, a clock other than
the high-speed system clock cannot be set as the peripheral hardware clock.
<3> Setting the main system clock as the CPU clock and selecting the division ratio (PCC register)
When CSS is cleared to 0, the main system clock is supplied to the CPU. To select the CPU clock
division ratio, use PCC0, PCC1, and PCC2.
CSS PCC2
0
(4) Example of setting procedure when
CHAPTER 6 CLOCK GENERATOR
Selection of Main System Clock and Clock Supplied to Peripheral Hardware
Main System Clock (f
1 High-speed system clock (f
PCC1 PCC0
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
Other than above
Preliminary User's Manual U17260EJ3V1UD
) Peripheral Hardware Clock (f
XP
) High-speed system clock (f
XH
CPU Clock (f ) Selection
CPU
f
XP
f /2 (default)
XP
2
f /2
XP
3
f /2
XP
4
f /2
XP
Setting prohibited
)
PRS
)
XH
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