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CHAPTER 5 CLOCK GENERATOR
User’s Manual U15104EJ2V0UD
5.3 Register Controlling Clock Generator
The clock generator is controlled by the processor clock control register (PCC).
PCC sets the CPU clock.
PCC is set with a 1-bit or 8-bit memory manipulation instruction.
Reset input sets PCC to 04H.
Figure 5-3. Format of Processor Clock Control Register (PCC)
Note
Bits 3 to 7 are read only.
Remarks 1. f
X
:
System clock oscillation frequency
2. ( ): Minimum instruction execution time: 2/f
CPU
at f
X
= 4.5 MHz operation
0
0
0
0
PCC2 PCC1 PCC0
PCC
FFFBH
04H
R/W
Note
7
6
5
4
Symbol
Address
After reset
R/W
0
7
6
3
2
0
1
0
0
PCC2
CPU cIock (f
CPU
) selection
PCC1 PCC0
0
0
0
1
0
0
1
1
0
1
1
0
0
Setting prohibited
Other than above
R/W
f
X
/2
f
X
/2
2
f
X
/2
3
f
X
/2
4
f
X
(0.89 s)
(1.78 s)
(3.56 s)
(7.11 s)
(0.45 s)
µ
µ
µ
µ
µ
