Fujitsu FR60 ユーザーズマニュアル
966
Chapter 50 Subclock Calibration Unit
4.Clocks
4. Clocks
The module operates with 3 different clocks: The 4 MHz clock OSC4, the 32 kHz clock OSC32 (ot the 100kHz
clock OSC100) and the peripheral clock CLKP. Synchronization circuits adapt the different domains.
clock OSC100) and the peripheral clock CLKP. Synchronization circuits adapt the different domains.
The clock frequencies have to fulfill the following requirements:
●
Clock ratio
T
OSC32/OSC100
> 2 x T
OSC4
+ 3 x T
CLKP
T
OSC4
< 1/2 x T
OSC32/OSC100
- 3/2 x T
CLKP
T
CLKP
< 1/3 x T
OSC32/OSC100
- 2/3 x T
OSC4
●
The input frequencies must not exceed the values given in Table
.
Table 4-1 Maximum operation frequencies
Table 4-2 Example of valid clock ratios which fulfill requirements 1 and 2
OSC32/OSC100
OSC4
CLKP
maximum
2 MHz
500 ns
10 MHz
100 ns
50 MHz
20 ns
OSC32
OSC100
OSC4
CLKP
maximum operation
speed
2 MHz
500 ns
2 MHz
500 ns
10 MHz
100 ns
50 MHz
20 ns
normal operation
32 kHz
31.25 us
100 kHz
10 us
4 MHz
250 ns
>2 MHz
500 ns