Fujitsu MB90460 Series, Hardware Manual, Page: 232 / 739

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CHAPTER 10 TIME-BASE TIMER
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Oscillation Stabilization Time Timer Function
The time-base timer is also used as the oscillation stabilization time timer for oscillation and the PLL
clocks.
The oscillation stabilization time is set for the interval from the time the counter counts up from "0" (count
clear) until the oscillation stabilization time bit overflows. When control returns from time-base timer
mode to PLL clock mode, the oscillation stabilization time starts from the middle of counting because the
time-base timer counter has been not cleared. Table 10.5-1 shows the clearing of the time-base counter and
the oscillation stabilization times.
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Clock Supply Function
The time-base timer supplies clocks to the watchdog timer. Clearing of the time-base counter affects
operation of the watchdog timer.
Table 10.5-1 Time-base Timer Counter Clearing and Oscillation Settling Times
Operation Counter clear TBOF clear Oscillation settling time
TBTC: Writing of 0 to TBR O O
Power-on reset
O O Oscillation clock oscillation stabilization time
Watchdog reset
Releasing of stop mode O O
Oscillation clock oscillation stabilization time
(at return to main clock mode)
Transition from oscillation clock mode
to PLL clock mode (MCS = 1
→
0)
O O PLL clock oscillation stabilization time
Releasing of time-base timer mode X X
PLL clock oscillation stabilization time (at
return to PLL clock mode)
Releasing of sleep mode X X
O: Available
X: Not available