7906 datasheet(129/531 Pages) RENESAS

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TIMER A

7906 Group User’s Manual Rev.2.0

7-26

7.4 Event counter mode

7.4.4 Selectable functions

The following describes the selectable pulse output, and two-phase pulse signal processing functions.

(1)

Pulse output function

The pulse output function is selected by setting the pulse output function select bit (bit 2 at addresses

5616 to 5816, 5A16, DA16) to “1.” When this function is selected, the TAjOUT pin is forcibly set for the

pulse output pin regardless of the corresponding bits of the port P2 and port P6 direction registers.

The TAjOUT pin outputs a pulse of which polarity is inverted each time a counter underflow or overflow

occurs. (Refer to Figure 7.3.5).

When the count start bit (addresses 4016, 4116) is “0” (count stopped), the TAjOUT pin outputs “L” level.

(2)

Two-phase pulse signal processing function (Timers A2, A4, A9)

For timers A2, A4, A9, the two-phase pulse signal processing function is selected by setting the two-

phase pulse signal processing select bits (bits 5 and 7 at address 4416, bit 7 at address C416) to “1.”

(See Figure 7.4.5.) Figure 7.4.6 shows the timer A2/A4/A9 mode registers when the two-phase pulse

signal processing function is selected.

For timers with two-phase pulse signal processing function selected, the timer counts two kinds of

pulses of which phases differ by 90 degrees. There are two types of the two-phase pulse signal

processing: normal processing and quadruple processing. In timer A2, normal processing is performed;

in timers A4 and A9, quadruple processing is performed.

For the port P2 and P6 direction registers’ bits corresponding to the pins used for two-phase pulse

input, be sure to set these bits for the input mode.

Fig. 7.4.6 Timer A2/A4/A9 mode registers when two-phase pulse signal processing function is selected

7906 Datasheet(PDF) 129 Page - Renesas Technology Corp