MB95630H Series
88 FUJITSU SEMICONDUCTOR LIMITED MN702-00009-2v0-E
CHAPTER 7 TIME-BASE TIMER
7.1 Overview
7.1 Overview
The time-base timer is a 24-bit free-run down-counting counter. It is
synchronized with the main clock divided by two, or with the main CR clock or
with the main CR PLL clock. The clock can be selected by the SCS[2:0] bits in
the SYCC register. The time-base timer has an interval timer function that can
repeatedly generate interrupt requests at regular intervals.
â– Interval Timer Function
The interval timer function repeatedly generates interrupt requests at regular intervals by using
the main clock divided by two, or using the main CR clock or using the main CR PLL clock as
the count clock.
• The counter of the time-base timer counts down so that an interrupt request is generated
every time a selected interval time elapses.
• The length of an interval time can be selected from the following 16 types.
Table 7.1-1 shows the interval times available for the time-base timer.
*1: F
CH
= 4 MHz
∴2/F
CH
= 0.5 μs
*2: F
CRH
= 4 MHz
∴1/F
CRH
= 0.25 μs
*3: F
MCRPLL
= 8 MHz
PLL multiplication rate = 2
F
CRH
× PLL multiplication rate = 4 MHz × 2
= 8 MHz
∴1/F
MCRPLL
= 0.125 μs
Table 7.1-1 Interval Times of Time-base Timer
Interval time if the main clock
is used
Interval time if the main CR
clock is used
Interval time if the main CR
clock is multiplied by a PLL
multiplication rate of 2
(2
n
× 2/F
CH
*1
)(2
n
× 1/F
CRH
*2
)(2
n
× 1/F
MCRPLL
*3
)
n=9 256 μs 128 μs 64 μs
n=10 512 μs 256 μs 128 μs
n=11 1.024 ms 512 μs 256 μs
n=12 2.048 ms 1.024 ms 512 μs
n=13 4.096 ms 2.048 ms 1.024 ms
n=14 8.192 ms 4.096 ms 2.048 ms
n=15 16.384 ms 8.192 ms 4.096 ms
n=16 32.768 ms 16.384 ms 8.192 ms
n=17 65.536 ms 32.768 ms 16.384 ms
n=18 131.072 ms 65.536 ms 32.768 ms
n=19 262.144 ms 131.072 ms 65.536 ms
n=20 524.288 ms 262.144 ms 131.072 ms
n=21 1.049 s 524.288 ms 262.144 ms
n=22 2.097 s 1.049 s 524.288 ms
n=23 4.194 s 2.097 s 1.049 s
n=24 8.389 s 4.194 s 2.097 s
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