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92
CHAPTER 5 CLOCK GENERATOR
Preliminary User’s Manual U13420EJ2V0UM00
Figure 5-3. Format of Processor Clock Control Register (PCC)
Address: FFFBH After Reset: 04H R/W
Note 1
Symbol
7
6
5
4
3
2
1
0
PCC
MCC
FRC
CLS
CSS
0
PCC2
PCC1
PCC0
MCC
Main system clock oscillation control
Note 2
0
Oscillation possible
1
Oscillation stopped
FRC
Subsystem clock feedback resistor select
0
Internal feedback resistor used
1
Internal feedback resistor not used
CLS
CPU clock status
0
Main system clock
1
Subsystem clock
CSS
PCC2
PCC1
PCC0
CPU clock (f
CPU
) select
0
0
0
0
f
X
0
0
1
f
X
/2
0
1
0
f
X
/2
2
0
1
1
f
X
/2
3
1
0
0
f
X
/2
4
1
0
0
0
f
XT
/2
0
0
1
0
1
0
0
1
1
1
0
0
Other than above
Setting prohibited
Notes 1. Bit 5 is Read Only.
2. When the CPU is operating on the subsystem clock, MCC should be used to stop the main system clock
oscillation. A STOP instruction should not be used.
Cautions 1. Bit 3 must be set to 0.
2. When the external clock is input, MCC should not be set.
This is because the X2 pin is connected to V
DD1
via a pull-up resistor.
Remarks 1. f
X
: Main system clock oscillation frequency
2. f
XT
: Subsystem clock oscillation frequency
Summary of Contents for mPD780065 Series
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