BAT32G1x9 user manual | Chapter 4 Clock generation circuit
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Rev.1.02
4.3.2
System Clock Control Register
(CKC).
This is the register that selects the CPU/peripheral hardware clock and the master system clock.
The CKC register is set by the 8-bit memory operation instruction.
After generating a reset signal, the value of this register changes to "00H".
Figure 4-3
Format of system clock control register (CKC)
Address: 40020404H
reset:
00HR/W
Note1
SYMBOL
7
6
5
4
3
2
1
0
CKC
CLS
The status of the CPU/Peripheral Hardware Clock (fCLK)
0
The main system clock (fMAIN)
1
Subsystem clock (fSUB).
CSSnote2
Selection of CPU/Peripheral Hardware Clock (fCLK)
0
The main system clock (fMAIN)
1
Subsystem clock (fSUB)
MCS
The state of the master system clock (fMAIN)
0
High-speed internal oscillator clock (fIH)
1
High-speed system clock (fMX)
MCM0 Note
2
Operational control of the main system clock (fMAIN)
0
Select the high-speed internal oscillator clock (fIH) as the main system clock (fMAIN)
1
Select the high-speed system clock (fMX) as the main system clock (fMAIN)
Note 1. bit7
and
bit5
are read-only bits.
2. It is forbidden to change the
value of the MCM0 bit
in
the state of placing the
CSS
position
"1".
Note f
HOCO
: The clock frequency of the high-speed internal oscillator (64MHz
maximum
).
f
IH
: Clock frequency of high-speed internal oscillator (64MHz
maximum
)
f
MX
: High-speed system clock frequency
f
MAIN
: The main system clock frequency
f
SUB
: Subsystem clock frequency
Note 1
You must set
bit0~3
to
"0".
2. Provide
a
clock with CSS bit
settings to the CPU and peripheral hardware. If you change
the CPU
clock, you also
change the clock of the peripheral hardware (except for the real-time clock,
15-bit interval timer, clock output/buzzer
output, and watchdog timer). Therefore, if you want to change
the clock of the CPU/peripheral hardware, you must
stop the peripheral functions.
3. If the secondary system clock is used as a peripheral hardware clock, the
operation of
the A/D
converter and
IICA
cannot
be guaranteed. For the operating characteristics of the peripheral hardware, refer to
the sections on each peripheral hardware
and
the
electrical characteristics
of the data sheet.
CLS
CSS
MCS
MCM0
0
0
0
0