APPLICATION
2.4 Timer 1, timer 2, and timer 3
3820 GROUP USER’S MANUAL
2–94
I
T
OUT
output active edge switch bit (bit 0)
The T
OUT
output active edge switch bit selects an initial level of the T
OUT
output.
When bit 0 is “0,” the output pulse from the P5
6
/T
OUT
pin is started at the “H” level.
When bit 0 is “1,” the output pulse from the P5
6
/T
OUT
pin is started at the “L” level.
I
T
OUT
output control bit (bit 1)
The T
OUT
output control bit controls the T
OUT
output.
When bit 1 is “0,” the T
OUT
output is disabled.
When bit 1 is “1,” the T
OUT
output is enabled.
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Timer 2 write control bit (bit 2)
The timer 2 write control bit controls writing to the timer 2.
When bit 2 is “0,” a simultaneous write operation to both the timer 2 latch and the timer 2 counter is
set.
When a value is written to the timer 2, the value is set into both the timer 2 latch and the timer 2
counter at the same time.
When bit 2 is “1,” a write operation to the latch only is set.
When a value is written into the timer 2, the value is set into the timer 2 latch only.
When a value is written into the timer 2 latch only, this rewritten value is transferred to the timer 2
counter at the first timer 2 counter underflow after rewriting.
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Timer 2 count source selection bit (bit 3)
The timer 2 count source selection bit selects a count source of the timer 2. Table 2.4.1 shows the
relation between the timer 2 count source selection bit and count sources.
I
Timer 3 count source selection bit (bit 4)
The timer 3 count source selection bit selects a count source of the timer 3. Table 2.4.2 shows the
relation between the timer 3 count source selection bit and count sources.
Table 2.4.1 Relation between timer 2 count source selection bit and count sources
bit 3
0
1
f(X
IN
)/16 (In low speed mode; f(X
CIN
)/16)
Timer 2 count source
Timer 1 underflow
Table 2.4.2 Relation between timer 3 count source selection bit and count sources
bit 4
0
1
f(X
IN
)/16 (In low speed mode; f(X
CIN
)/16)
Timer 3 count source
Timer 1 underflow
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Timer 1 count source selection bit (bit 5)
The timer 1 count source selection bit selects a count source of the timer 1. Table 2.4.3 shows the
relation between the timer 1 count source selection bit and count sources.
Table 2.4.3 Relation between timer 1 count source selection bit and count sources
Count source examples
f(X
IN
) = 8 MHz
500 kHz
—
f(X
CIN
) = 32.768 kHz
2.048 kHz
32.768 kHz
0
1
bit 5
f(X
IN
)/16 (In low speed mode; f(X
CIN
)/16)
f(X
CIN
)
Timer 1 count source