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5.3.4 Select function
The following describes the selective gate and pulse output functions.
(1) Gate function
The gate function is selected by setting the gate function select bits (bits 4 and 3 at addresses 56
to 5A
) to "10
16
the TAi
pin's input signal. Table 5.3.3 lists the count valid levels.
IN
Figure 5.3.5 shows an example of operation selecting the gate function.
When selecting the gate function, set the port P5 and port P6 direction registers' bits which correspond
to the TAi
pin for the input mode. Additionally, make sure that the TAi
IN
width equal to or more than two cycles of the count source.
Table 5.3.3 Count valid levels
Gate function select bits
b4
1
1
Note: The counter does not count while the TAi
" or "11
" The gate function makes it possible to start or stop counting depending on
.
2
2
b3
0
While TAi
1
While TAi
7751 Group User's Manual
Count valid level (Duration when counter counts)
pin's input signal is "L" level
IN
pin's input signal is "H" level
IN
pin's input signal is not at the count valid level.
IN
TIMER A
5.3 Timer mode
pin's input signal has a pulse
IN
16
5–15
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