M38203M4 Datasheet, PDF (178/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.4 Timer 1, timer 2, and timer 3
sCounters
The counters count the count source^V1. Figure 2.4.7 shows the structure of the timer counters.
The value of the counter is decremented by 1 each time a count source is input.
The division ratio of the counters is represented by the following expression.
Division ratio of the counter =
1
the counter initial value + 1
When the timer is read out, the value of the counter (count value) is read out.
For the rewriting operation for the value of the counter, refer to “2.4.1 Explanation of operations,
(2) Rewriting the value of the counter and the latch.”
V1: For count source selection, refer to “2.4.2 Related registers, (2) Timer 123 mode register.”
qTimer 1 counter and timer 3 counter
Timer 1 and timer 3
b7 b6 b5 b4 b3 b2 b1 b0
Timer 1 and timer 3 (T1, T3) [Address 2416, 2616]
B
Functions
At reset R W
0 •Set “0016 to FF16” as timers 1 or 3 count value. 1
to •The value of the counter is decremented by
7 1 each time a count source is input.
•The values of each timer are set to the
respective counters.
•The respective count values are read out by
reading each timer.
qTimer 2 counter
Timer 2
b7 b6 b5 b4 b3 b2 b1 b0
Timer 2 (T2) [Address 2516]
B
Functions
At reset R W
0 ^{•Set “0016 to FF16” as timer 2 count value.}
1
•The value of the counter is decremented by
1 each time a count source is input.
•When timer 2 write control bit is “0,” the value
1 _{of the timer 2 is set to the timer 2 counter.}
0
to _{•The timer 2 count value is read out by reading}
7 _{the timer 2.}
Fig. 2.4.7 Structure of timer counters
2–92
3820 GROUP USER’S MANUAL