Operations Of Time-Base Timer - Fujitsu MB90335 Series Hardware Manual

MB90335 Series
9.5

Operations of Time-base Timer

The time-base timer has functions of interval timer and clock supply to peripheral
functions.
■ Operation of Interval Timer Function (Time-base Timer)
Interval timer function generates interrupt requests at regular intervals. In order to function as an interval
timer, setup in Figure 9.5-1 is needed.
Address
0000A9
: Used bit
: Unused bit
0 : Set to "0".
: Set to "1".
1
• The time-base timer counter continues count-up synchronizing to the internal count clock (two division
of oscillation clock) as long as the clock oscillate.
• Count-up from "0" is made when the counter is cleared; the interrupt request flag bit (TBOF) is set to
"1" when the bit for the interval timer overflows. In this case, interrupts are generated at selected
intervals based on the cleared if the interrupt request output is permitted (TBIE = 1).
• The interval time may be longer than the set period by the clearance operation of the time-base timer.
■ Oscillation Stabilization Wait Time Function
The time-base timer can also be used for the oscillation clock or timer for PLL clock oscillation
stabilization wait time. The oscillation stabilization wait time is the duration elapsed by counting up from
"0" (count clear) to the moment at which the bit for oscillation stabilization wait time overflows. When the
mode recovers from the time-base timer mode to the PLL clock mode or main clock mode, the oscillation
stabilization wait time is the duration from the middle of counting because the time-base timer counter has
not cleared. Table 9.5-1 shows the clearance operation of the time-base timer counter and oscillation stabilization
wait time.
CM44-10137-6E
Figure 9.5-1 Setting of Time-base Timer
bit15 bit14 bit13
TBTC Reserved
H
1
FUJITSU MICROELECTRONICS LIMITED
bit12 bit11 bit10 bit9 bit8
TBIE
TBOF TBR TBC1 TBC0
0 0
CHAPTER 9 TIME-BASE TIMER
9.5 Operations of Time-base Timer
bit7 bit0
(WDTC)
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