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9.5 Operation of the Timebase Timer
9.5
Operation of the Timebase Timer
This section describes the operation of the interval timer function, the oscillation
stabilization interval timer function, and the clock supply function.
s Operation of the Interval Timer Function (Timebase Timer)
The interval timer function generates an interrupt request for each interval
The stabilization in
Figure 9.5-1 "Stabilization of the Timebase Timer" is required to all the timer
to operate as an interval timer.
Figure 9.5-1 Setting of the Timebase Timer
The timebase timer continues counting up as long as the clock oscillates.
If the timebase timer counter is cleared (TBTC: TBR = "0"), the counter counts up from
"000000000000000000B". When the specified interval timer bit overflows, the interrupt
request flag bit (TBOF) of the timebase timer control register (TBTC) is set to "1". If the
overflow occurs while the interrupt request enable bit is set to Enabled (TBIE = "1"), interrupt
requests are output at every specified interval based on the time when the counter was
cleared.
The interval may become longer than the time set because of timebase timer clearing.
s Oscillation Stabilization Wait Interval Timer Function
The timebase timer is also used as the oscillation time timer for oscillation and the PLL clocks.
The timebase timer is also used for the oscillation stabilization interval of the oscillation clock
and the PLL clock. The timebase timer counts up the oscillation stabilization interval since it
has the value "000000000000000000B" (counter cleared) and until it detects the oscillation
stabilization interval. When the timebase timer returns from timebase timer mode to PLL clock
mode, the oscillation stabilization interval indicates only the portion from the middle of counting
because the timebase timer counter has not been cleared.
TBC0
RESV
TBIE TBOF TBR TBC1
0
1
0
bit15 bit14 bit13 bit12
bit10
bit9
bit8
: Used
0 : Set 0.
1: Set 0.
- : Undefined bit
bit11
--
Address
0000A9H