7733 datasheet(139/940 Pages) RENESAS

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TIMER A

7733 Group User’s Manual

6–28

(2) Pulse output function

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

addresses 5616 to 5A16) to “1.” When this function is selected, pin TAiOUT is forcibly set as the pulse

output pin independent of the corresponding bit of the port P5 or port P6 direction register. And then,

pin TAiOUT outputs a signal of which polarity is inverted each time an underflow or overflow occurs

(Refer to Figure 6.3.6).

When the count start flag (address 4016) = “0,” in other words, when counting is stopped, pin TAiOUT

outputs “L” level.

(3) Two-phase pulse signal processing function (Timers A2 to A4)

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

phase pulse signal processing selection bits (bits 5 to 7 at address 4416) to “1.” (Refer to Figure

6.4.6.) Figure 6.4.8 shows the timer A2, A3, and A4 mode registers when the two-phase pulse signal

processing function is selected.

In a timer with the two-phase pulse signal processing function selected, two kinds of pulses of which

phases differ by 90 degrees are counted. There are two types of the two-phase pulse signal processing:

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

A4, quadruple processing is performed. In timer A3, either normal processing or quadruple processing

can be selected by the two-phase pulse signal processing type selection bit (bit 7 at address 5916).

Some bits of the port P5 and P6 direction registers correspond to pins used for the two-phase pulse

input. Set these bits for the input mode.

6.4 Event counter mode

Timer A2 mode register (address 5816)

Timer A3 mode register (address 5916)

Timer A4 mode register (address 5A16)

0: Reload count type

1: Free-run count type

g: Bit 7 of the timer A3 mode register is used to select the two-phase pulse signal

processing type of timer A3.

Normal processing is selected when this bit = “0,” and quadruple processing

is selected when this bit = “1.”

Bit 7 of the timer A2/A4 mode register is ignored. (It may be “0” or “1.”)

Fig. 6.4.8 Timer A2, A3, and A4 mode registers when two-phase pulse signal processing function is selected

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