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269
CHAPTER 15 WATCH TIMER
■ Cycle of Clock Supply
The watch timer supplies an operation clock to the oscillation stabilization wait time timer of the subclock
and the watchdog timer. Table 15.1-2 shows the cycles of clocks supplied from the watch timer.
Note:
The frequency of the subclock (SCLK) is a value for 2 division/4 division of the clock inputted to the
low-speed oscillation pin (X0A and X1A) or the internal CR oscillation clock.
The division ratio is set by the SCDS bit of the PLL/subclock control register (PSCCR).
When using the internal CR oscillation clock, see "CHAPTER 6 CLOCK SUPERVISOR". Please con-
sider the frequency difference of built-in CR oscillation when you use built-in CR oscillation clock as a
sub-clock.
Table 15.1-2 Cycle of Clock Supplied from Watch Timer
Where to Supply Clock Clock Cycle
Timer for oscillation stabilization wait time of subclock
2
14
/SCLK(4.000 s)
Watchdog timer
2
10
/SCLK(125 ms)
2
13
/SCLK(1.000 s)
2
14
/SCLK(2.000 s)
2
15
/SCLK(4.000 s)
SCLK: Subclock frequency
The parenthesized values are provided when the subclock operates at 8.192 kHz.