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CHAPTER 5 CLOCK GENERATOR
User’s Manual U19780EJ2V0UD
157
5.6.5 Clocks supplied to CPU and peripheral hardware
The following table shows the relation among the clocks supplied to the CPU and peripheral hardware, and setting
of registers.
Table 5-3. Clocks Supplied to CPU and Peripheral Hardware, and Register Setting (78K0/KB2-A)
Supplied Clock
Clock Supplied to CPU
Clock Supplied to Peripheral Hardware
XSEL MCM0 EXCLK
Internal high-speed oscillation clock
0
×
×
X1 clock
1
0
0
Internal high-speed oscillation clock
External main system clock
1
0
1
X1 clock
1 1 0
External main system clock
1
1
1
Remarks
XSEL: Bit 2 of the main clock mode register (MCM)
CSS:
Bit 4 of processor clock control register (PCC)
MCM0: Bit 0 of MCM
EXCLK: Bit 7 of the clock operation mode select register (OSCCTL)
×
: don’t
care
Table 5-4. Clocks Supplied to CPU and Peripheral Hardware, and Register Setting (78K0/KC2-A)
Supplied Clock
Clock Supplied to CPU
Clock Supplied to Peripheral Hardware
XSEL CSS MCM0
EXCLK
Internal high-speed oscillation clock
0
0
×
×
X1 clock
1
0
0
0
Internal high-speed oscillation clock
External main system clock
1
0
0
1
X1 clock
1 0 1 0
External main system clock
1
0
1
1
Internal high-speed oscillation clock
0
1
×
×
1 1 0 0
X1 clock
1 1 1 0
1 1 0 1
Subsystem clock
External main system clock
1 1 1 1
Remark
XSEL: Bit 2 of the main clock mode register (MCM)
CSS:
Bit 4 of the processor clock control register (PCC)
MCM0: Bit 0 of MCM
EXCLK: Bit 7 of the clock operation mode select register (OSCCTL)
×
: don’t
care