7702 datasheet(103/217 Pages) RENESAS

103 / 217 page

TIMER A

7702/7703 Group User’s Manual

5–15

5.3 Timer mode

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 5616

to 5A16 ) to “102” or “112.” The gate function makes it possible to start or stop counting depending on

the TAiIN pin’s input signal. Table 5.3.3 lists the count valid levels.

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 TAiIN pin for the input mode. Additionally, make sure that the TAiIN pin’s input signal has a pulse

width equal to or more than two cycles of the count source.

Table 5.3.3 Count valid levels

Gate function select bits

Count valid level (Duration when counter counts)

While TAiIN pin’s input signal is “L” level

While TAiIN pin’s input signal is “H” level

Note: The counter does not count while the TAiIN pin’s input signal is not at the count valid level.

7702 Datasheet(PDF) 103 Page - Renesas Technology Corp