CHAPTER 6 CLOCK GENERATION FUNCTION
User’s Manual U13850EJ6V0UD
184
6.3.1 Control registers
(1) Processor clock control register (PCC)
This is a specific register. It can be written to only when a specified combination of sequences is used (see
3.4.9
Specific registers
). This register can be read/written in 8-bit or 1-bit units.
After reset:
03H
R/W
Address: FFFFF074H
<7>
<6>
5
4
3
<2>
1
0
PCC
FRC
MCK
0
0
0
CK2
CK1
CK0
FRC
Selection of internal feedback resistor for subclock
0
Use
1
Do not use
MCK
Operation of main clock (main clock)
0
Operating
1
Stopped
CK2
Notes 1, 2
CK1
CK0
Selection of CPU clock
0
0
0
f
XX
0
0
1
f
XX
/2
0
1
0
f
XX
/4
0
1
1
f
XX
/8
1
X
X
f
XT
(subclock)
Notes 1.
If manipulating CK2, do so in 1-bit units. In the case of 8-bit manipulation, do not change the
values of CK1 and CK0.
2.
When the CPU operates on the subclock (CK2 = 1), do not set the HALT or software STOP mode.
Cautions 1. While CLKOUT is being output, do not change the CPU clock (the value of the CK2 to CK0
in the PCC register).
2. Even if the MCK bit is set to 1 during main clock operation, the main clock is not stopped.
The CPU clock stops after the subclock is selected.
3. Be sure to set bits 3 to 5 to 0.
Remark
X: don’t care
Содержание V850/SB1
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