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CHAPTER 11 CLOCK OUTPUT CONTROLLER
User’s Manual U19780EJ2V0UD
320
Figure 11-2. Format of Clock Output Selection Register (CKS)
Address: FF40H After reset: 00H R/W
Symbol
7 6 5
<4>
3 2 1 0
CKS
0
0
0
CLOE CCS3 CCS2 CCS1 CCS0
CLOE
PCL output enable/disable specification
0
Clock division circuit operation stopped. PCL fixed to low level.
1
Clock division circuit operation enabled. PCL output enabled.
PCL output clock selection
Note 1
CCS3 CCS2 CCS1 CCS0
f
SUB
=
32.768 kHz
f
PRS
=
10 MHz
f
PRS
=
20 MHz
0 0 0 0
f
PRS
Note 2
10
MHz
Setting
prohibited
Note 3
0 0 0 1
f
PRS
/2
5 MHz
10 MHz
0 0 1 0
f
PRS
/2
2
2.5 MHz
5 MHz
0 0 1 1
f
PRS
/2
3
1.25 MHz
2.5 MHz
0 1 0 0
f
PRS
/2
4
625 kHz
1.25 MHz
0 1 0 1
f
PRS
/2
5
312.5 kHz
625 kHz
0 1 1 0
f
PRS
/2
6
156.25 kHz
312.5 kHz
0 1 1 1
f
PRS
/2
7
−
78.125 kHz
156.25 kHz
1 0 0 0
f
SUB
32.768
kHz
−
Other than above
Setting prohibited
Notes 1.
The frequency that can be used for the peripheral hardware clock (f
PRS
) differs depending on the
power supply voltage.
Supply Voltage
Use frequency range of peripheral hardware clock (f
PRS
)
2.7 V
≤
V
DD
≤
5.5 V
f
PRS
≤
20 MHz
1.8 V
≤
V
DD
< 2.7 V
f
PRS
≤
5 MHz
(The values shown in the table above are those when f
PRS
= f
XH
(XSEL = 1).)
2.
If the peripheral hardware clock (f
PRS
) operates on the internal high-speed oscillation clock (XSEL =
0)when 1.8 V
≤
V
DD
< 2.7 V, setting CCS3 = CCS2 = CCS1 = CCS0 = 0 (output clock of PCL: f
PRS
) is
prohibited.
3.
The
PCL output clock prohibits settings if they exceed 10 MHz.
Caution Set CCS3 to CCS0 while the clock output operation is stopped (CLOE = 0).
Remarks 1.
f
PRS
: Peripheral hardware clock frequency
2.
f
SUB
: Subsystem clock frequency