MB95630H Series
MN702-00009-1v0-E
FUJITSU SEMICONDUCTOR LIMITED
57
CHAPTER 3 CLOCK CONTROLLER
3.9 Operation of Prescaler
3.9
Operation of Prescaler
The prescaler generates count clock sources to different peripheral functions.
■
Operation of Prescaler
The prescaler generates count clock sources from a clock whose frequency is generated by
dividing the machine clock(MCLK),or from buffered signals from the time-base timer(F
CH
/2
7
,
F
CH
/2
8
, F
CRH
/2
6
, F
CRH
/2
7
, F
MCRPLL
/2
6
, or
F
MCRPLL
/2
7
), and then supplies them to different
peripheral functions. The prescaler keeps operating while the machine clock and the clocks
from the time-base timer are being supplied.
Table 3.9-1, Table 3.9-2 and Table 3.9-3 list the count clock sources generated by the
prescaler.
Table 3.9-1
Count Clock Sources Generated by Prescaler (F
CH
)
Count clock source
frequency
Frequency
(F
CH
= 20 MHz,
MCLK = 10 MHz)
Frequency
(F
CH
= 32 MHz,
MCLK = 16 MHz)
Frequency
(F
CH
= 32.5 MHz,
MCLK = 16.25 MHz)
MCLK/2
5 MHz
8 MHz
8.125 MHz
MCLK/4
2.5 MHz
4 MHz
4.0625 MHz
MCLK/8
1.25 MHz
2 MHz
2.0313 MHz
MCLK/16
0.625 MHz
1 MHz
1.0156 MHz
MCLK/32
0.3125 MHz
0.5 MHz
0.5078 MHz
F
CH
/2
7
156.25 kHz
250 kHz
253.9 kHz
F
CH
/2
8
78.125 kHz
125 kHz
126.95 kHz
Table 3.9-2
Count Clock Sources Generated by Prescaler (F
CRH
)
Count clock source
frequency
Frequency
(F
CRH
= 4 MHz,
MCLK= 4 MHz)
MCLK/2
2 MHz
MCLK/4
1 MHz
MCLK/8
0.5 MHz
MCLK/16
0.25 MHz
MCLK/32
125 kHz
F
CRH
/2
6
62.5 kHz
F
CRH
/2
7
31.25 kHz