3 clock selection register (ckscr), Clock selection register (ckscr) – FUJITSU F2MCTM-16LX User Manual
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CHAPTER 5 CLOCKS
5.3
Clock Selection Register (CKSCR)
The clock selection register (CKSCR) is used to switch among the main clock, PLL
clocks and subclock, also used to select an oscillation stabilization wait interval and a
PLL clock multiplier.
■
Configuration of the Clock Selection Register (CKSCR)
Figure 5.3-1 Configuration of the Clock Selection Register (CKSCR)
bit9
bit8
CS2
CS1
CS0
Multiplication rate select bit
Parenthesized values are examples calculated at
an oscillation clock (HCLK) frequency of 4 MHz.
0
0
0
1
×
HCLK (4 MHz)
0
0
1
2
×
HCLK (8 MHz)
0
1
0
3
×
HCLK (12 MHz)
0
1
1
4
×
HCLK (16 MHz)
1
1
0
6
×
HCLK (24 MHz)
1
1
1
Setting disabled
bit10
MCS
PLL clock select bit
0
Select PLL clock
1
Select main clock
bit11
SCS
Sub clock select bit
0
Select sub clock
1
Select main clock
bit13 bit12
WS1 WS0
Oscillation stabilization wait time select bit
Parenthesized values are examples calculated at an
oscillation clock (HCLK) frequency of 4 MHz.
0
0
2
10
/HCLK (approx. 256
µ
s)
0
1
2
13
/HCLK (approx. 2.05 ms)
1
0
2
17
/HCLK (approx. 32.77 ms)
1
1
2
15
/HCLK
(
approx.
8.19 ms, other than power-on reset)
2
16
/HCLK
(
approx.
16.38 ms, power-on reset only)
bit14
MCM
PLL clock operation bit
0
Operating in PLL clock
1
Operating in main clock or sub clock
bit15
SCM
Sub clock operation bit
0
Operating in sub clock
1
Operating in main clock or PLL clock
Address
15
14
13
12
11
10
9
8
Reset value
0000A1
H
SCM
MCM
WS1
WS0
SCS
MCS
CS1
CS0
11111100
B
R
R
R/W R/W R/W R/W R/W R/W
CS2(PSCCR register: bit8)
HCLK
: Oscillation clock
R/W
: Read/Write
R
: Read only
: Reset value