200
CHAPTER 9 8-BIT TIMER/EVENT COUNTER
(1) 8-bit interval timer
When an 8-bit timer/event counter is used as an interval timer, it generates an interrupt request at any time
intervals set in advance.
Table 9-1. Interval Time of 8-Bit Timer/Event Counter
Minimum Interval Time
Maximum Interval Time
Resolution
2
2
×
1/f
X
(400 ns)
2
10
×
1/f
X
(102.4
μ
s)
2
2
×
1/f
X
(400 ns)
2
3
×
1/f
X
(800 ns)
2
11
×
1/f
X
(204.8
μ
s)
2
3
×
1/f
X
(800 ns)
2
4
×
1/f
X
(1.6
μ
s)
2
12
×
1/f
X
(409.6
μ
s)
2
4
×
1/f
X
(1.6
μ
s)
2
5
×
1/f
X
(3.2
μ
s)
2
13
×
1/f
X
(819.2
μ
s)
2
5
×
1/f
X
(3.2
μ
s)
2
6
×
1/f
X
(6.4
μ
s)
2
14
×
1/f
X
(1.64 ms)
2
6
×
1/f
X
(6.4
μ
s)
2
7
×
1/f
X
(12.8
μ
s)
2
15
×
1/f
X
(3.28 ms)
2
7
×
1/f
X
(12.8
μ
s)
2
8
×
1/f
X
(25.6
μ
s)
2
16
×
1/f
X
(6.55 ms)
2
8
×
1/f
X
(25.6
μ
s)
2
9
×
1/f
X
(51.2
μ
s)
2
17
×
1/f
X
(13.1 ms)
2
9
×
1/f
X
(51.2
μ
s)
2
10
×
1/f
X
(102.4
μ
s)
2
18
×
1/f
X
(26.2 ms)
2
10
×
1/f
X
(102.4
μ
s)
2
12
×
1/f
X
(409.6
μ
s)
2
20
×
1/f
X
(104.9 ms)
2
12
×
1/f
X
(409.6
μ
s)
Remarks 1.
f
X
: main system clock oscillation frequency
2.
( ) : at f
X
= 10.0 MHz operation
(2) External event counter
The number of pulses of an externally input signal can be measured.
(3) Square wave output
A square wave of any frequency can be output.
Table 9-2. Square Wave Output Range of 8-Bit Timer/Event Counter
Minimum Pulse Width
Maximum Pulse Width
Resolution
2
2
×
1/f
X
(400 ns)
2
10
×
1/f
X
(102.4
μ
s)
2
2
×
1/f
X
(400 ns)
2
3
×
1/f
X
(800 ns)
2
11
×
1/f
X
(204.8
μ
s)
2
3
×
1/f
X
(800 ns)
2
4
×
1/f
X
(1.6
μ
s)
2
12
×
1/f
X
(409.6
μ
s)
2
4
×
1/f
X
(1.6
μ
s)
2
5
×
1/f
X
(3.2
μ
s)
2
13
×
1/f
X
(819.2
μ
s)
2
5
×
1/f
X
(3.2
μ
s)
2
6
×
1/f
X
(6.4
μ
s)
2
14
×
1/f
X
(1.64 ms)
2
6
×
1/f
X
(6.4
μ
s)
2
7
×
1/f
X
(12.8
μ
s)
2
15
×
1/f
X
(3.28 ms)
2
7
×
1/f
X
(12.8
μ
s)
2
8
×
1/f
X
(25.6
μ
s)
2
16
×
1/f
X
(6.55 ms)
2
8
×
1/f
X
(25.6
μ
s)
2
9
×
1/f
X
(51.2
μ
s)
2
17
×
1/f
X
(13.1 ms)
2
9
×
1/f
X
(51.2
μ
s)
2
10
×
1/f
X
(102.4
μ
s)
2
18
×
1/f
X
(26.2 ms)
2
10
×
1/f
X
(102.4
μ
s)
2
12
×
1/f
X
(409.6
μ
s)
2
20
×
1/f
X
(104.9 ms)
2
12
×
1/f
X
(409.6
μ
s)
Remarks 1.
f
X
: main system clock oscillation frequency
2.
( ) : at f
X
= 10.0 MHz operation